Creamy Chimichurri Roast Chicken

Preparation

1. Sauce

   Step 1

   Pulse 5 garlic cloves, 2½ cups (packed) cilantro leaves with tender stems, 2 cups (packed) parsley leaves with tender stems, ¼ cup red wine vinegar, 1 Tbsp. plus 1 tsp. Diamond Crystal or 2¼ tsp. Morton kosher salt, 1 Tbsp. plus 1 tsp. dried oregano, 2 tsp. crushed red pepper flakes, and ¼ cup extra-virgin olive oil in a food processor until combined and herbs are very finely chopped but not puréed. Transfer mixture to a medium bowl and add 1 cup plain whole-milk Greek yogurt and remaining ½ cup extra-virgin olive oil. Whisk vigorously until emulsified (makes about 2½ cups).

   Do ahead: Sauce can be made 3 days ahead. Cover and chill. Whisk just before using.

2. Chicken and assembly

   Step 2

   Place one 3½–4-lb. whole chicken, backbone removed, patted dry, breast side up, on a cutting board; open up against surface as much as possible. Using your palms, press firmly on breastbone to flatten breast (you may hear a crack). Transfer to a large bowl and rub all over with 2 tsp. Diamond Crystal or 1¼ tsp. Morton kosher salt and ¾ cup sauce. Cover and chill at least 2 hours and, preferably, up to 12 hours (no need to bring to room temperature before roasting).

   Step 3

   Place a rack in middle of oven; preheat to 375°. Transfer chicken to a wire rack set inside a large rimmed baking sheet; spread any marinade left in large bowl over skin. Roast chicken, rotating baking sheet halfway through, until skin is deep golden brown and an instant-read thermometer inserted into thickest part of a thigh registers 165°, 50–60 minutes. Let rest 10 minutes.

   Step 4

   Transfer chicken to a platter. Whisk remaining sauce in medium bowl if it has separated and serve alongside.