2 lbs. mixed potatoes (any combination of white, yellow, purple or red)
3 tablespoons olive oil
4 pints cherry tomatoes
4 Tablespoons olive oil
4 garlic cloves, minced
1 Tablespoon thyme leaves
½ Cup pitted oil cured black olives
splash of white wine (optional)
6 (7-8 ounce) filets of cod
6 Tablespoons butter
3 Tablespoons capers
salt and freshly ground pepper
lemon for serving
Preheat oven to 425°. Line two rimmed sheet pans with parchment paper
Thinly slice potatoes into 1/8” rounds. Place in a large bowl and toss with duck fat or olive oil. Assemble the potatoes by overlapping slices, in rows, to create six separate rectangles that are approximately 4” by 6” or slightly larger than each cod filet. Make sure to overlap slices by at least ½” to account for shrinkage during roasting and ensuring stability when serving. If you have extra slices left over, feel free to layer them in the center of the shingled potato rectangles. Sprinkle each one liberally with salt and freshly ground pepper. Roast for 30 minutes, rotating the pan mid-way through, until the edges of the potatoes are golden and crispy.
Once the potatoes have been cooking for approximately 20 minutes, toss tomatoes in a large bowl with olive oil, thyme leaves, and olives. Season the mixture with salt and pepper. Spread onto prepared baking sheet and sprinkle with white wine, if using. Roast for 25 minutes until the tomatoes have burst and are just beginning to brown in spots.
Once the potatoes are crispy and golden, remove them from the oven. Place a cod filet in the center of each potato rectangle, season with salt and pepper. Put 1 tablespoon of butter on top of each filet. Diving the capers evenly among each filet, sprinkle on top of the butter.
Return the sheet pan back to the oven and bake for 15 minutes more, until fish is opaque and flakes easily with a fork.
Using a spatula, gently transfer each potato rectangle and filet to a serving plate along with tomatoes. Serve with a lemon wedge.