Ranch Chicken

Steps

1. Start with the ranch sauce. In a bowl, whisk the mayonnaise, sour cream, and buttermilk until smooth. Grate the garlic clove into it, then add two-thirds of the fresh chives, very finely snipped, the chopped fresh dill, the juice of half a lemon, a pinch of salt, and a grind of pepper. Cover and refrigerate for at least 30 minutes: the garlic and herbs infuse and the sauce thickens.
2. Place each chicken breast between two sheets of plastic wrap and pound the thickest part with the bottom of a saucepan, working from the center out, until it's an even 3/4 inch (2 cm) thick all over.
3. Season the breasts on both sides with the rest of the fine salt. Let them sit for 30 minutes at room temperature, or up to 24 hours uncovered on a plate in the fridge.
4. Mix the garlic powder, onion powder, dried dill, dried parsley, dried chives, paprika, and the rest of the pepper. Rub the mixture between your fingers to crush the herbs: they stick better and release their aroma.
5. Pat the breasts dry with paper towels, brush them with 1 tablespoon of oil, then press the ranch seasoning onto every side in an even layer.
6. Heat a large cast-iron skillet or grill pan over medium-high heat with the remaining oil for 2 minutes, until the oil shimmers. Lay in the breasts, smoothest side down, and leave them alone for 4 to 5 minutes: the underside should be golden brown and release from the pan on its own.
7. Flip the breasts, lower the heat to medium, and add the butter. When it foams, tilt the pan and baste the chicken with a spoon for 3 to 5 minutes. Insert a thermometer into the thickest part: it's done at 165°F (74°C). You can pull it at 160°F (72°C), since resting finishes the job. If the crust darkens too fast, finish in a 400°F (200°C) oven for 5 to 8 minutes.
8. Move the breasts to a cutting board and let them rest for 5 minutes. Meanwhile, cut the remaining lemon half into wedges. Taste the sauce and thin it with a spoonful of buttermilk if it's too thick to pool.
9. Spread the ranch sauce over the bottom of a serving dish in a generous layer. Slice the chicken on the bias into 1/2-inch (1 cm) slices and fan them over the sauce. Pour the juices from the board over the top, scatter with the rest of the fresh chives, and set the lemon wedges alongside. Serve right away.