Step 1

Place a rack in middle of oven and set a large cast-iron skillet on rack; preheat oven to 425°. Pat chicken dry and rub with 2 tsp. salt; season with pepper.

Step 2

Stir shallot and lemon juice in a small bowl; season with salt and pepper. Set aside.

Step 3

Pat chicken dry again; rub with oil. Carefully place skin side down in preheated skillet and roast, turning skin side up halfway through, until an instant-read thermometer inserted into thickest part registers 150°, 20–25 minutes. Transfer chicken to a cutting board, leaving fat behind, and let rest (temperature will rise as meat sits).

Step 4

Place skillet on stovetop over medium heat (be careful of that hot handle). Add bread and season with salt and pepper. Toast, stirring often and scraping up browned bits, until golden, about 4 minutes. Add more oil if pan looks dry. Using a slotted spoon, transfer croutons to a plate.

Step 5

Add butter and anchovies to same skillet and cook, breaking up anchovies with a spoon, until butter is melted. Add peas, remaining ½ tsp. salt, and 2 Tbsp. water; season with pepper. Cook, stirring occasionally, until peas are bright green and warmed through, about 4 minutes. Remove from heat.

Step 6

Cut chicken meat from bones and slice. Stir croutons, herbs, and reserved shallot mixture into peas; season with salt and pepper. Divide among plates; top with chicken. Serve with lemon wedges.