You can have this complete Fish and Mashed Potatoes dinner on the table in just 20 minutes, perfect for your busy weeknight meals!

This fish and mashed potatoes recipe guides you through sautéing white fish fillets with a simple lemon butter sauce and making creamy mashed potatoes. It's a delicious combination!
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How to Time This Meal Perfectly
This dish has several components: fish, mashed potatoes, and a light lemon butter sauce to pour over the fish.
To time this meal perfectly, cook the potatoes first because they take longer than the fish. While the potatoes cook, prepare the fish. When the mashed potatoes are ready to go on the table, cook the fish so it's served hot.
- Prep: Before you begin, have your ingredients and cooking utensils ready.
- Cook the Potatoes: Start by cooking the potatoes. As you peel and cut them, put them in the pot of water as it heats up to prevent discoloring.
- Make the Sauce: Combine butter, minced garlic, lemon juice, and chopped parsley in a saucepan over low heat.
- Prepare the Fish: While the potatoes cook, rinse, dry, and season the fish with salt and pepper. Dredge in flour.
- Cook the fish in butter and olive oil in a heavy skillet.
- Mash: Drain and mash the potatoes while the fish cooks.
- Serve hot: Once both the fish and mashed potatoes are cooked, serve them immediately while they're hot. Garnish with chopped parsley.

What You Need
- Thin white fish filets such as wild-caught snapper, mahi mahi, tripletail, hogfish, trout, etc.
- Russet or Yukon Gold potatoes (they both work great!)
- Unsalted butter
- Olive oil
- Cream or milk, to mix in the potatoes
- Lemons
- Fresh herbs such as parsley, basil, or thyme
- Salt and black pepper

How To Make Creamy Garlic Mashed Potatoes
This recipe is simple to make.
After boiling the potatoes, drain them in a colander and return them to the warm pot they were cooked in for a few minutes. This helps dry out the potatoes so the potatoes are creamier.
- Bring a large pot of water to a boil over high heat, adding a generous pinch of salt to the water.
- Peel and dice the potatoes. Place them in the pot of water as it heats up.
- Once the water reaches a boil, reduce the heat to medium and simmer the potatoes until they are very tender, 12-15 minutes.
- While the potatoes are cooking, warm the heavy cream in a small pot over low heat.
- Drain the cooked potatoes in a colander, then return them to the warm pot they were cooked in. Add butter and mash until smooth.
- Gradually pour half of the warm cream into the pot, stirring to combine. Add more cream until the desired creamy consistency is achieved. If you add too much cream, you can reduce the heat and let the excess evaporate.
- Season the mashed potatoes with salt and pepper to taste. Adjust seasoning as needed before serving.

Mashed Potato Add-Ins
The potatoes can be moistened with heavy cream, or you can use milk, sour cream, crème fraiche, Greek yogurt, or simply lots of butter.
For additional flavor, add green onions, chives, roasted garlic, caramelized onions, grated cheese, horseradish, Dijon mustard, or crispy bacon.
How To Sauté Fish
Sautéing fish is an easy way to cook it on the stovetop.
To sauté fish, heat a combination of butter and olive oil in a heavy-bottomed skillet. Cook the fish until golden brown on each side, ensuring it's cooked through.
- In a small saucepan, make the sauce. Heat butter, minced garlic, the juice of half a lemon, and chopped parsley over low heat. Cover and let it heat while you make the fish.
- Wash and pat dry the fish with a paper towel.
- Lightly season the fish with salt and pepper. Dust the fish with flour and shake off the excess.
- In a large skillet over medium heat, add 1 tablespoon of butter and 1 tablespoon of olive oil. When the butter is melted, add two cloves of minced garlic. Cook for about 20 seconds until fragrant; add fish in a single layer.
- Cook the fish for 2-3 minutes without moving. Flip and cook until the second side is cooked through and easily flakes when pierced with a fork, another 2-3 minutes.
To cook four fillets at once, use two skillets.
Or, wipe out the pan after the first batch and cook the remaining fish.
Should I Flour Fish Before Cooking?
Flouring fish before cooking can make the fish a little crispy. It can also help seasonings stick better. But if you prefer a lighter touch, you can skip the flour.
I made two fillets coated with salt, pepper, and all-purpose flour. I made another two that I just seasoned with salt and pepper.
You can see in the photos that the fish coated in flour developed a golden color and the one without the flour stayed relatively white after cooking.

Interestingly, the fish coated in flour held together better after being cooked. The flour coating helped maintain its shape, making it easier to transfer from the pan to the plate.
For a gluten-free meal, all-purpose flour can be replaced with brown or white rice flour. Just note that rice flour won't brown and will have an appearance similar to fish seasoned only with salt and pepper.
Storing Leftovers
Store the leftovers in an airtight container. You can layer the fish over the potatoes and refrigerate for a day or two.
Reheat the fish with the potatoes in a skillet. You can add a few drops of milk or cream to the potatoes to moisten them if they need it.
Garnish For This Fish Dinner
Serve the fish right over the mashed potatoes and pour the lemon butter sauce over the fish. Garnish with chopped parsley and lemon wedges.
Choose a colorful side dish such as green peas. My kids love fish, mashed, and peas!
Sides for Fish and Mashed Potatoes
Here are a few of my favorite low-starch side dish recipes to pair with this seared fish dinner. Given the starchy nature of the potatoes, a delicate vegetable dish will perfectly complement the fish and potatoes.
These sides have great color and taste to make your meal one to remember.
- Steamed Broccoli and Carrots
- Roasted Cauliflower and Carrots with Garlic
- Roasted Asparagus
- Roasted Baby Eggplant Poppers
- Steamed Brussels Sprouts
- Roasted Cauliflower and Asparagus with Carrots
- Crispy Oven Roasted Broccoli and Garlic
- Oven Roasted Spaghetti Squash
Final Thoughts
This Fish and Mashed Potatoes with Lemon Butter Sauce is so good! Talk about comfort food! It's the perfect lazy Sunday dinner.
I lightly season the fish with salt and pepper. You can also season with a little use Old Bay or blackened seasoning for added flavor.
Dredge the fish in flour before sautéing which enhances its appearance and helps keep the fish in one piece for serving.
Mashed potatoes are so easy to make. Use a hand-held masher or potato ricer to mash the potatoes until smooth. Add butter and cream, a few tablespoons at a time, until the potatoes are creamy.
Make sure to season the mashed potatoes. Potatoes tend to soak up a lot of salt and need extra seasoning.
On the side, steam some frozen peas or pick one of our favorite vegetable recipes to go with the fish.
Most of all, have fun. This is an easy fish dinner that everyone will enjoy.
FAQ
Yes! Creamy mashed potatoes are a versatile side dish that pairs nicely with all kinds of fish dishes, whether fried, baked, grilled, or pan-seared.
You can add herbs such as parsley, basil, and chives. Cheese (such as Parmesan, cheddar, or Gruyere) can also be added. Roasted garlic cloves and carmelized onions can also be added for additional flavor.
Absolutely! Mashed potatoes can be prepared in advance and reheated when needed. Just store them in an airtight container in the refrigerator. When ready to serve, gently reheat them on the stovetop or in the microwave, adding a touch more butter or cream for extra richness if desired.
Mashed potatoes can be flavored with many seasonings. Experiment with sour cream, plain yogurt, or cream cheese for creaminess. Enhance with grated cheddar, parmesan, or Gruyere for a cheesy twist. Add depth with chopped garlic, roasted garlic, or crispy fried onions. For freshness, add chopped herbs like parsley, basil, and chives.
Parsnips: Parsnips are root vegetables with a sweet and nutty flavor. They can be cooked and mashed like potatoes and have less starch.
Sweet Potatoes: While sweet potatoes are higher in carbohydrates and natural sugars, they are still lower in starch than traditional white potatoes. They have a sweeter flavor and can be mashed similarly to potatoes. Try our buttery whipped sweet potato recipe.
Cauliflower: Cauliflower is a low-carb substitute for mashed potatoes. It can be mashed or pureed to resemble mashed potatoes. Lower in starch and carbohydrates, cauliflower is a great low-starch and low-carb option.
"📖 Recipe"

Fish and Mashed Potatoes
Ingredients
- 2 pounds Russet or Yukon Gold Potatoes peeled and diced
- 8-10 tablespoons unsalted butter, divided
- ¼ cup heated heavy cream or milk,
- 4 6-ounce thin white fish filets, (snapper, tripletail, hogfish, trout, mahi, etc.)
- 2 tablespoons olive oil
- 4 garlic cloves
- 2 lemons
- ¼ cup all-purpose flour (use rice flour for gluten-free)
- 3 tablespoons chopped parsley or another herb (chives, basil, thyme, etc.)
- salt and freshly ground black pepper
Instructions
For the mashed potatoes
- Bring a big pot of water to a boil over high heat. Add a big pinch of salt to the water.
- Peel and dice the potatoes. As the potatoes are cubed, place them in the pot of boiling water to prevent discoloring.
- When the water starts to boil, reduce the heat to medium and simmer until the potatoes are VERY SOFT, about 15 minutes.
- Drain the potatoes in a colander, then return them to the pot they were cooked in. Mash them with a handheld potato masher until smooth.
- Add 3 tablespoons of butter to the mashed potatoes, mixing well. Add more to taste.
- Slowly pour half of the cream over the potatoes and mix to combine. Add more cream until the potatoes are creamy. If you add too much cream, turn the heat on low and let the cream evaporate a bit.
- Season the mashed potatoes with salt to taste.
Cook the fish while the potatoes are cooking
- In a small saucepan, heat 4 tablespoons of butter, 2 cloves minced garlic, the juice of half a lemon, and 3 tablespoons chopped parsley over low heat. Cover and let it heat while the fish is cooking.
- Rinse the fish fillets under cold water and pat dry with paper towels. Lightly season with salt and pepper. Place the flour in a shallow bowl and drop the fish fillets in the flour, making sure to coat both sides evenly. Shake off the excess.
- Over medium heat, add 1 tablespoon of butter and 1 tablespoon of olive oil to the pan. When the butter is melted, add two cloves of smashed garlic. Cook for about 30 seconds until fragrant; add fish in a single layer.
- Cook the fish for 2-3 minutes. Turn and cook until the fish is cooked through and flakes when pierced with a fork, another 2-3 minutes. Remove to a plate. Discard the garlic.
- Wipe the pan clean and cook the remaining fish.
- Plate the mashed potatoes with the fish. Spoon the butter sauce over all. Serve with lemon wedges.
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