As I mentioned in the opening musings of this week's menu, I ended up using Barramundi when I was working on this recipe and was very happy with the results. While Sole is ideal, any delicious thin, white fish will be great here. Besides, who are we kidding, this dish is about the brown butter and lemon sauce, the fish is just the vehicle for it.
I dredged my fish with spelt flour because I'm keen on it and always have some on hand. Spelt adds a nutty flavor and makes a bit more of a crust than regular flour, but don't go out of your way for it (or do and then make Spelt Matcha Coffeecake). All-purpose flour is also perfect here, and if you are gluten-free a little cornmeal is a dream.
Traditionally this dish is made with clarified butter but I always skip this step and just use regular unsalted butter since eventually the same pan will be used for making the brown butter pan sauce. Purist may bark, but as long as you are careful and don't burn your butter using clarified butter seems like an unnecessary step in a home kitchen.
For the celery purée:
1 large or 2 small celery roots
1 medium Yukon Gold potato (or 2 smaller ones)
1 Tablespoon Kosher salt
1/3 cup olive oil
6 cloves of garlic, peeled
1-2 Tablespoons heavy cream, optional
For the fish:
2 small filets of sole (or similar fish) per person, about 6 ounces of fish per person
1/2 cup of flour (spelt, all-purpose, cornmeal - your choice)
2 teaspoons Kosher salt
6 Tablespoons of butter
1 Tablespoon capers, drained
1 small handful of parsley
aluminum foil (to keep your fish warm)
To cook the celery purée:
Peel the celery root with a knife and cut it into small chunks. Place it in a medium pot. Peel the potato with a peeler and cut it into small chunks. Place the potato in the same pot as the celery root and cover the vegetables with enough water to have 1" of water above them. Add 1 Tablespoon kosher salt to the water. Cook over medium-high heat until both vegetables are tender.
Meanwhile place the olive oil and whole, peeled garlic in a small pot. Bring the oil and garlic to a gentle simmer and cook for about 10 minutes. You want to cook the garlic slowly not only so that it doesn't burn but also because you want the garlic to soften and the oil to be infused with the garlic. Once the garlic starts to look a little less bright and opaque it is done. Remove the pot from the heat and set aside.
Once the celery root and potato are completely tender drain them. You want the vegetables to be so tender you could completely smoosh them with your fingers. Anything less will not give you a smooth purée.
Place the celery root and potato with the garlic in a food processor. You may need to work in batches depending on the size of your processor, and you can always mash everything with a fork or use a ricer the result will be bit chunkier but still very tasty. With the processor running slowly drizzle in the oil. Once everything is incorporated taste the purée. Does it need a little more salt? Is it a little thick and maybe needs a splash of cream? I've made this puree many times and sometimes it feels like it needs a little cream and sometimes it's perfect as is. I think it depends on how much water the vegetables absorb in cooking.
To cook the fish:
Pick your parsley from its stem and mince it.
Sprinkle the flour on a plate. Add the salt and mix it mix the back of a spoon or a clean finger.
Pat the fillets dry with a paper towel.
Heat 2 tablespoons of butter in a large sauté pan over medium heat. While it melts, dredge both sides of 2 fillets in the flour. Place them in the hot pan and lower the heat to medium-low. Cook them for 3 minutes then carefully turn them with a metal or fish spatula. Cook them for 1- 2 minutes on the other side. This will depend on how thin or thick your filets are.
Place the cooked filets on a plate and cover them with foil to keep warm.
Add one more Tablespoon of butter and repeat the process with the remaining fillets. If you are cooking for more than two people you will need to add a Tablespoon of butter each time you add more filets to the pan. Yo may also want to keep your fish warm in a 200º oven if you are cooking for many.
Once all your fish is cooked. Make the sauce by adding 3 Tablespoons of butter to your sauté pan. Heat it over medium-high heat. First it will foam, then it will look broken and separated, then the milk solids will start to brown. Remove the pan from the heat as soon as the milk solids start taking on some color. The butter will continue to cook from the residual heat. You want the butter and the milk solids to be a light to medium amber but no darker. Let the butter sit off the heat for a minute then squeeze a whole lemon over it. Add the capers and stir.
Plate the fish on a bed of the celery root puree. Pour some brown butter caper sauce over it and sprinkle the parsley on top.