Pan-Seared Cod with Lemon Butter

Steps

1. 20 to 40 minutes before cooking, pat the cod pieces dry with paper towels and salt them on all sides. Set them on a rack, uncovered, in the fridge.
2. Meanwhile, crush the garlic cloves in their skins with the flat of a knife. Drain the capers, and rinse them if they're salt-packed. Zest the lemon on a fine grater, then squeeze 2 tablespoons of juice. Chop the parsley.
3. Right before cooking, pat the cod dry again: beads of water will have come to the surface. Season with pepper. Heat an 11-inch (28 cm) stainless steel or cast iron skillet over high heat for 2 minutes empty, then add the oil: it should shimmer and give off a first wisp of smoke.
4. Lay the pieces skin side down, or best-looking side down if skinless, setting them into the pan away from you so you don't get splattered. If they have skin, press each piece with a flexible spatula for 10 seconds so the skin doesn't curl. Lower the heat to medium-high.
5. Don't touch anything for 4 to 5 minutes, until the flesh has turned opaque two-thirds of the way up and the edges are golden. The fish releases on its own once the crust has formed: if it sticks, wait another 30 seconds.
6. Flip the cod with a thin spatula. Add 40 g of the butter, the garlic, and the thyme. When the butter foams, tilt the pan toward you and baste the fish nonstop with a spoon for 1 to 2 minutes. Take it out at 125 to 131°F (52 to 55°C), measured at the thickest point: the flesh is pearly and separates into flakes under light finger pressure.
7. Move the cod to warm plates, crust side up, and let it rest 2 minutes: it will climb another 3 to 5°F (2 to 3°C).
8. Remove the garlic and thyme from the pan. Lower the heat to medium, add the remaining 40 g of butter, and let it foam for 1 to 2 minutes, until it turns hazelnut brown and smells like cookies. Add the capers: they crackle and turn crisp in 30 seconds.
9. Off the heat, pour in the lemon juice (it will bubble hard), add the zest and parsley, and swirl the pan to combine. Spoon this lemon caper butter over each piece of cod and serve right away.