Fish & Mashed Potato Casserole

Yummy Sole, mashed potato and cheesy casserole 1Casseroles for me translate as the ultimate comfort food, served piping hot with a crisp, cool and leafy salad on the side. Some casseroles however do strike to me as a delicate luxury; delicate in flavor, delicate in textures and of course served with a certain grace. And this particular one with its haughty airs might as well be served at the Downton Abbey table.  Delicate flakes of Sole fish, a velvety Béchamel sauce and petite pieces of pasta…. But between you, me and Mrs. Patmore, it is actually great comfort food. Why? Because it comes with mashed potatoes! And that says it all!


The trick to using pasta is to match the right pasta shape and size with the consistency and flavor of the sauce. Fish is delicate in texture and Sole has a delicate flavor as well so I chose Tripolini for this particular recipe. It is small enough not to overwhelm the fish flakes but will hold the white sauce well. You can choose to use Pipette, Gnocchetti or mini versions of Farfalle or whatever you might have in your larder.

Boiled Pasta

Bring a pot of water to boil, add some salt and the pasta. When the pasta is done, strain and run cold water over it to stop it from cooking further and remove the starch.

add flour to oil white sauceAdd the olive oil and the flour to heavy based saucepan. If using butter, melt the butter and then add the flour.

White sauce flour in olive oil

Blend them both until absolutely smooth or you will end up with starchy lumps in the white sauce.

Chicken Stock

While the actual Béchamel recipe calls for just milk, I prefer to use chicken broth as well. I just think the flavor is richer. So you can combine the chicken broth with the milk and make sure they are cool or at least not warm. Managing temperatures is crucial to a smooth and velvety sauce.

frying flour white sauce

Bring the flour mixture to a bubble on low heat making sure that you are stirring all the time. Flour has the tendency to brown very quickly at the base of the pan. When the flour begins to change color and that butter cookie aroma rises in the kitchen, it’s time to flood the saucepan.

adding stock to flour

Yes, I said to flood. So the trick is to bring down the temperature of the flour and the saucepan as fast as you can. This prevents the flour from cooking further and the sauce from thickening immediately while giving you some time to whisk it to complete smoothness.

White Sauce Ready

So remove from flame and quickly add all the milk and broth in one go. Whisk the contents of the saucepan until no lumps are visible. Return to simmer and keep stirring while the sauce thickens. Add the salt to season.

add raosted garlic mashed potatoes

Mash the boiled potatoes and add the roasted garlic. Yes, that does look like fried garlic but that’s only because I forgot and chopped it up first but this did brown in the oven so technically its roasted!!!

Add milk and roasted garlic to mashed potatoes

Add the milk and salt to the mashed potatoes.

Mashed Potato through seive

Once the potatoes are thoroughly mashed, pass them through a sieve. Yep, you hear the crazy food blogger. PASS the MASHED POTATOES through A SIEVE! Believe me it is worth the effort. Even regular everyday mashed potatoes; they come out super fine and creamy!

Shredded Mild Chedder

Grate the cheddar cheese. Even though I love mature and sharp Cheddar, I didn’t want the cheese to take over the flavor so I have used mild cheddar for this recipe. Before you begin to wonder, those tomatoes don’t go in this casserole, they are for the Seared Tomato On Leafy Greens salad.

Sole Fish fillets

Heat 2 tablespoons of vegetable oil in the frying pan and add the Sole fillets. Let the fish cook for 3 minutes on the same side.

Pan Frying sole fish

Turn over the fillets and cook for another 2 minutes.

Break up the fish

Roughly break up the fillets. Do not end up making a fine mince please… we need chunky flakes for some texture.

Pasta tossed in Fish

Toss in the pasta and season with salt.

Pasta and fish in Ramkins

While you can serve this in a casserole dish, I like to serve this in ramekins for the visual appeal.  Lightly fill each ramekin with the fish and pasta mixture. Do not press the mixture down or pack it too tightly.

Pour White sauce in ramkins

Spoon in the warm Béchamel sauce while stirring the pasta slightly so that the sauce is evenly distributed.

Piling mashed potatoes on ramkins

Add generous dollops of the mashed potatoes evenly between the ramekins and smoothen it over, leaving behind some 6 tablespoons of the mashed potatoes.

add cheese to mashed potatoes

Add half the grated Cheddar to the remaining potatoes.

mashed potato

Mix them well.

topping ramkins

Now roughly heap 2 tablespoons of the potato and cheese mixture on the mashed potato layer.

fish casserole ready to bake

Sprinkle the remaining cheddar on top and your casseroles are ready to go in the oven.

savory fish pudding

Bake the casseroles for 30 minutes or more at 180C/350F till the cheese is golden and bubbling.

enjoy cheesy fish casserole

Enjoy with a complimenting salad on the side. I like to serve this with a Seared Tomato on Leafy Greens Salad.

Fish & Mashed Potato Casserole
Serves: 3 Ramekins
Prep Time:
Cooking Time:
Total time:
  • 4 Fillets of Sole or other mild flavored Fish
  • 2 Tablespoons of Oil
  • 1 ½ cup Tripolini Pasta or any other pasta – Boiled
  • ½ cup Mild Cheddar Cheese – Grated
  • ½ Teaspoon Salt
  • For The White Sauce
  • 4 Tablespoons Flour
  • 4 Tablespoons Butter OR 6 Tablespoons Olive Oil
  • 1 cup Milk - Cold
  • 1 Cup Chicken Stock- Cold
  • 1 Teaspoon Salt
  • For The Mashed Potatoes
  • 1 ½ cup Boiled Potatoes
  • 2 Cloves Garlic - Roasted
  • ½ Cup Milk
  • ½ Teaspoon Salt
  1. Boil the pasta and strain when done. Rinse with cold water.
  2. Melt the butter in a saucepan.
  3. Remove from flame and stir in the flour until smooth and no lumps remain.
  4. Return to low heat.
  5. When the flour begins to change color, add all the milk and broth in one go and whisk briskly to remove all lumps that might form.
  6. Let simmer while stirring continuously till sauce thickens and season with salt.
  7. Mash the boiled potatoes, salt, roasted garlic and milk together until fine and then push the mashed potatoes through a sieve.
  8. Grate the cheese.
  9. Pan-fry the fish fillets in the vegetable oil. 3 minutes on one side and 2 minutes on the other side.
  10. Break up the fish in the frying pan. Add the pasta and salt and toss until mixed.
  11. Spoon the pasta and fish mixture into the ramekins.
  12. Pour over some white sauce distributing evenly around the pasta leaving 1cm to the brim of the ramekin.
  13. Pile 4 tablespoons of mashed potatoes onto each ramekin and smoothen it over.
  14. Add half the grated cheese to the remaining 6 tablespoons of mashed potatoes and pile equally onto each ramekin.
  15. Sprinkle the remaining Cheddar on top.
  16. Bake for 30 min at 180C /350F or Gas Mark 4 till bubbling and golden.
  17. Serve piping hot.