sauteed cod with arugula, beets, and horseradish creme fraiche

We got our first csf share (see here) yesterday: an 8 pound cod that I carried home, tail sticking out, in a plastic grocery bag (thank god I didn’t have to take the T.) John did the csf last year with some friends, and I got in on eating some of the freshest seafood of my life as a result and, thanks to youtube, also learned how to filet a fish. This year, I was ready; I sharpened some knives and got to work. Five minutes later (yeah right, try 45 minutes) I had my perfectly (ha) filleted and skinned cod, along with some for the freezer and soup pot full of scraps to make (the best ever) fish stock.
So, what to make with the season’s first cod? I turned to my bookshelves for an answer, skimming indexes for c-o-d. Leafing through Suzanne Goin’s Sunday Suppers at Lucques, I stumbled on a simple and charming preparation actually intended for halibut, but easily adaptable to cod. This makes a light hearted dinner or a fancy lunch. As Goin notes, the visual presentation is stunning with snow white fish, vibrant greens, and ruby beets. Mine was perhaps a little less so than hers – I actually meant to make this for dinner last night, but sadly interrupted, my beets sat dressed in the fridge overnight. They tasted great, but dyed the dressing and the shallots a lovely shade of purple which ended up in a puddle on the bottom of our plates. Also, cod just doesn’t hold together like halibut. Not only did it flake apart a little as it cooked, but I also managed to drop some of it on my sandal-clad foot while spooning it out of the pan. Purple plates and burnt toes aside, this is a mighty pretty, light, and tasty meal for a warm evening. 
Best of all, this dish comes together in no time at all (well ok, unless you’re filleting your own fish with my filleting skills.) The fish can be marinated ahead, the beets cooked ahead and dressed just before serving, the horseradish crème fraiche is a synch, and the whole thing is super easy to assemble. Enough for 4 as a main course or 6-8 as an appetizer.

For the Cod
4 skinless cod fillets
The zest of one lemon
2 tbsp olive oil plus more for cooking
1 tsp chopped thyme leaves
Salt and pepper

Marinate the Cod: Combine all the ingredients in a small bowl, cover, and let set in the refrigerator at least 2 hours but up to 6. 

For the Vegetables
4 big handfuls of washed arugula
1 bunch small purple beets (about 6)
2 tbsp sliced shallots
1 tbsp minced shallots
1 tbsp red wine vinegar
1 tbsp balsamic vinegar
The juice of half a lemon
3 tbsp olive oil
Salt and pepper
Olive oil and lemon juice to serve

 Cook the Beets: Cut the tips and the tops off the beets (save them to sautee!) and put the roots in a small sauce pan with water to cover and a pinch of salt. Cook until tender when pierced with a fork, 20-40 minutes depending on their size. Drain and cover with cold water, then carefully rub the peels off with your fingers. Quarter the beets and set aside in a medium bowl with the sliced shallots. 
Make the Dressing: Combine the minced shallots, red wine vinegar, balsamic vinegar, and lemon juice in a small bowl. Whisking vigorously, slowly pour in the olive oil. Season with salt and pepper and set aside.

For the Crème Fraiche 
¼ cup crème fraiche
2 tbsp heavy cream
1 tsp lemon juice
1 ½ tbsp prepared horseradish
½ tsp salt

Make the Crème Fraiche: combine all the ingredients in a small bowl and set aside.
Cook the Cod: Sprinkle the cod fillets with salt on both sides. Heat a large sautee pan over high heat. Once hot, generously coat the bottom with olive oil and carefully lay the cod fillets in the pan. Cook undisturbed for 2-3 minutes then flip and reduce the heat to medium-low. Continue cooking 1-3 minutes (depending on the size of the fillets) until lightly browned and cooked though. Try not to over-cook the fish, though cod shouldn’t be served rare like salmon or halibut. You want it just cooked through and no longer transparent inside. 
Assembly: Arrange the arugula on a large plate or platter. Toss the beets and sliced shallots with the dressing and spoon overtop the arugula. Drizzle a little crème fraiche over the beets and carefully lay the fish on top. Spoon more crème fraiche over each fillet and then drizzle the whole thing with olive oil and a generous squeeze of lemon. Serve immediately with lemon wedges on the side.