Baked Fillet of Flounder Stuffed with Spinach Recipe

30/11/2022 by Living the Gourmet 34 Comments

Flounder fillets are cooked to flaky perfection, rolled with a herbed breadcrumb stuffing, and set over a baby spinach sauteed with garlic and capers. Easy to make, and featuring only simple ingredients, these stuffed flounder fillets make for a deliciously elegant weeknight dinner.

However, let’s start off with one truism – seafood can be intimidating to prepare. Full stop. For starters, seafood features an array of irregular textures, ranging from delicate and flaky (bass and cod) to oily and thick (swordfish and salmon) to firm or even rubbery (squid, octopus and certain shark varieties). Then tack on a truly vast array of flavor profiles that run the gamut from light and clean (haddock and fluke) to tasting like the saltwater it’s been fished from (sardines, herring, and mackerel), and one might be forgiven for asking “Where do you start?” and then once you’ve found a starting point, you might further ask “How do you get it right?”

The answer is to start with what you’re comfortable with, and branch out from there.

To that point, I believe that every at-home chef or aspiring dinner-party virtuoso should have at least one ‘really’ good fish recipe in their repertoire. I’m talking about the kind of fish recipe that’s not only delicious, and therefore impresses the palate, but that also ‘looks’ excellent, thereby combining great flavors with equally great visuals.

And, you guessed it, that’s where today’s Stuffed Flounder Fillets come in.

Below, I’ll be providing you with an ingredient checklist for each part of the recipe, and some key substitutions. After that, I’ll be offering up some prep and handling tips, before moving onto the recipe itself.

Now, without further delay, let’s get to it.

Baked Fillet of Flounder Stuffed with Spinach Recipe

What to Expect – Recipe Overview

Taste and Texture

This super simple flounder recipe combines the delicate, flaky texture of flounder with a stuffing made from Italian-style breadcrumbs, fresh parsley, capers, celery, garlic, and Parmesan cheese. The stuffing provides a savory and herbal flavor profile, with just a hint of brine from the capers, wrapped in the baked flounder. The flounder itself remains tender and moist, creating a delightful contrast with the crisped coating and savory stuffing.

Difficulty Level

This is a recipe where I would recommend having some experience handling fish. While this isn’t necessarily a hard or complex recipe, there are a few things can go wrong. Poor handling of the fish can result in the flounder filets breaking apart or tearing, either during the rolling process or cooking, or even cross-contamination. Meanwhile, prepping the stuffing and sautéing the spinach, while certainly not hard, combine to add additional steps to an already moderately difficult recipe. However, if you have some experience preparing seafood, there really is no reason to shy away from this recipe.

Preparation Process

Stuffing Preparation: We start off by heating olive oil in a cast iron pan, and then sauté the parsley, garlic, and celery. Once that’s done, we add in the capers, caper juice, breadcrumbs, lemon juice, cheese, and a touch more olive oil to create the stuffing mixture. Easy.
Assembling the Flounder Rolls: This is where things get a bit tricky. We open the flounder filets so that they are flat, and then very gently spread the stuffing mixture on each flounder filet. After that’s done, we gently roll them up, and secure them closed with toothpicks. You must take care not to tear or overwork the fish. Finally, we place the rolls on a baking rack or baking sheet with a drizzle of olive oil, give them a dusting of paprika, oregano, and extra breadcrumbs.
Baking the Flounder: We finish the rolls by baking them in a preheated oven at 350°F for 20-25 minutes. The fish is done when it flakes easily with just the press of a fork.
Sautéed Spinach: To wrap things up, while the flounder bakes we sauté baby spinach with walnuts, garlic, sea salt, red pepper flakes, and olive oil until the spinach is wilted and the walnuts are toasted. And that’s the recipe.

Pairings

One of the best things about this recipe is just how easy it is to pair. Here are a few of my favorites.

Pasta Pairing. My ideal pairing would be to serve this stuffed flounder alongside linguine topped with either a creamy white sauce, or tossed with a simple garlic and oil sauce.
Seafood Lover Pairings. Fried crab cakes made with either fresh crab or lump crab meat, or fried tuna cakes would also be a delicious pairing. Stuffed oysters or clams would also be a lovely pairing. Grilled lobster would also be a delicious pairing.
Dipping Sauce. Yes, tartar sauce would be a delicious pairing, but I would also suggest any dipping sauce that uses melted butter as a base.
Rice Pilaf. Additionally, consider serving this dish with a side of lemony rice pilaf
Salad. The simplest pairing, would of course be a simple mixed green salad with a light vinaigrette.
Wine Pairing. A crisp white wine, such as Sauvignon Blanc or Pinot Grigio, would also be an excellent accompaniment to this meal.

Ingredient Checklist – Everything You’ll Need

For the Flounder:

6 fresh flounder fillets
- Tips: For best quality, ensure the flounder is as fresh possible and boneless.
- Substitute: Sole or tilapia would be good options if preferred.

For the Stuffing:

1¼ cups of Italian style seasoned bread crumbs
- Note: Yes, you can use gluten-free breadcrumbs if needed.
- Tip: Yes, you can adjust the amount of breadcrumbs to suit your taste, adding or removing up to about a quarter of a cup as desired.
½ cup of chopped Italian parsley, stems removed and chopped
- Substitute: Any mix of your preferred fresh herbs will work for this recipe. In particular, as good substitutes, I would recommend fresh cilantro, oregano, and basil. You might also throw in some chopped green onions either as part of the stuffing or for garnish.
1 tbs. capers plus 1 tbs. of caper juice, chopped
- Tip: Do not rinse the capers, we want the briny flavor. Seriously, I don’t know how or why this trend of rinsing capers started, but it makes absolutely no sense. Capers – sans the brine – are bitter. The brine is what gives capers their taste.
- Substitute: Chopped olives, either plain black or kalamata, would be my go-to.
1 stalk of celery, chopped fine
- Note: Adds a nice crunch to the stuffing.
- Substitute: This might sound odd, but chopped green or red bell pepper would be my go-to.
4 cloves of garlic, chopped fine
- Note: Use more or less garlic according to taste.
- Substitute with garlic powder in a pinch (¼ teaspoon per clove).
Juice of ½ lemon
- Tip: We’re using fresh lemon juice as it has a brighter, more citrusy flavor.
- Note: Be sure to reserve a few lemon wedges for serving, as we’ll be giving the stuffed fillets a squeeze of lemon right before eating.
- Substitute: Lime works well.
¼ cup of grated Parmesan or Romano cheese
- Note: Ensure the cheese is freshly grated for the best texture.
- Tip: Use Pecorino Romano for a sharper flavor.
- Substitute: Feel free to get creative with your choice of cheese. There’s no wrong way to do this.
Olive oil, for drizzling
- Tip: As always, I recommend using extra virgin olive oil for the best flavor.

For the Sautéed Spinach:

4 cups baby spinach
- Note: Yes, you can use regular spinach if baby spinach is not available; just chop it roughly.
- Substitute: Swiss chard or kale are the go-to.
3/4 cup walnut pieces
- Substitute: Pine nuts or slivered almonds.
3-4 cloves of garlic, chopped
- The amount of garlic can be adjusted to taste.
Sea salt
- Adjust the amount based on your preference.
¼ tsp. red pepper flakes
- Add more or less based on the desired heat level.
- Substitute with a pinch of cayenne pepper.
Olive oil
- Use for sautéing the spinach and walnuts.

Frequently Asked Questions (FAQ)

What tools do I need to prepare this recipe?

Fillet Knife: A fillet knife essential for cleanly cutting the flounder filets, and I really do recommend getting one if you prepare fish often.
Mixing Bowl: This goes without saying, but a large mixing bowl is a must for combining the stuffing ingredients. You might also consider a small bowl or two, or even ramekins, for holding chopped ingredients.
Small Pan: A small pan for sautéing the stuffing mixture.
Large Skillet: Preferably cast iron, but stainless steel or copper frying pan will also do, to sauté the initial stuffing ingredients.
Baking Dish: Use a baking dish, baking sheet, or a baking pan to cook the flounder rolls.

Can I use a whole flounder instead of fillets?

Yes, you can use a whole flounder and stuff that with the same mixture we’re putting in the rolls. However, you will need to adjust the cooking time and method if prepping a whole flounder rather than fillets.

How do I ensure the fish fillets don't fall apart when rolling?

You want to handle the fillets as gently as possible and use toothpicks to secure the rolls seam side down.

What is the ideal cooking time and temperature?

The ideal temperature for this recipe is 350 degrees F, as directed in the recipe card. You’ll want to bake the stuffed flounder for 20-25 minutes, as mentioned below.

How do I know when the fish is cooked?

The flounder should be opaque and easily flake when tested with a fork. The cooking time may vary slightly depending on the thickness of your fish fillets.

Can I make any changes to the stuffing?

Naturally! Experiment with different cheeses, herb mixtures, or greens.

Do I need any special equipment to prepare this recipe?

Not at all. This recipe is designed to be easily prepared right in your home kitchen using only common kitchen tools and accessible ingredients.

Stuffed Filet of Flounder

5 Stars 4 Stars 3 Stars 2 Stars 1 Star

4.4 from 5 reviews

Author: Living the Gourmet
Total Time: 30 minutes
Yield: 6 1x

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Ingredients

Units Scale

6 slices of filet of flounder

For the Stuffing:

1 1/4 cups of Italian style seasoned bread crumbs
1/2 cup of chopped Italian parsley - stems removed and chopped
1 tbs. capers plus a tbs. of caper juice - chopped
1 stalk of celery - chopped fine
4 cloves of garlic - chopped fine
Juice of 1/2 lemon
1/4 cup of grated Parmesan or Romano cheese
Olive oil - for drizzling
Paprika and Dried Oregano for dusting over the fish

For the Sautéed Spinach:

4 cups baby spinach
3/4 cup walnut pieces
3 - 4 cloves of garlic - chopped
Sea salt
1/4 tsp. Red pepper flakes
Olive oil

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Instructions

Preheat oven to 350 degrees F.
Heat a large cast iron frying pan with 2 tbs. olive oil.
Add the chopped parsley, chopped garlic and celery and toss for minute.
Add the capers and caper juice and toss.
Add the breadcrumbs, lemon juice and cheese and give a good drizzle of olive oil and toss.
Remove from the heat.
Place the flounder flat on a plate and line the flounder with a thin layer of the breadcrumb mixture.
Roll and carefully seal with a toothpick. Be gentle since the flounder will rip apart.
Place on a rack in a baking pan, if you do not have a pan with a rack, that’s ok, just drizzle a little olive oil in the pan and place the flounder rolls in a baking pan.
Sprinkle the flounder with paprika and dried oregano. You may dust the tops of the flounder with a little of the extra breadcrumbs and a drizzle of olive oil.
Bake 20-25 minutes or until the fish flakes easily with a fork.

For the Sautéed Spinach:

Heat a large cast iron frying pan with 2 tbs. olive oil.
Add the walnut pieces, sprinkle with sea salt and toss for a minute.
Remove the walnuts from the pan and set aside.
Add another 2 tbs. of olive oil and the chopped garlic. Toss for a minute or two until the garlic becomes fragrant, Do Not burn the garlic.
Add the spinach, a sprinkle of sea salt and a ¼ tsp. red pepper flakes and toss until the spinach is gently wilted, Do Not over cook.
Add in the walnut pieces and toss and remove from the heat with a slotted spoon to drain any excess moisture.

Prep Time: 10 minutes
Cook Time: 20 minutes
Category: Main Dish
Method: Broil

Nutrition

Serving Size: 6

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And that’s our Baked Fillet of Flounder Stuffed with Spinach. If you enjoyed today’s recipe, or have any questions or suggestions, be sure to let us know in the comments below! We always love hearing from you.

Happy Cooking!