1½ lb. brussels sprouts, trimmed, halved
¼ cup extra-virgin olive oil
½ tsp. kosher salt, plus more
Freshly ground black pepper
¼ cup honey
⅓ cup sherry vinegar or red wine vinegar
¾ tsp. crushed red pepper flakes
3 Tbsp. unsalted butter
3 scallions, thinly sliced on a diagonal
1 tsp. finely grated lemon zest
DirectionsPlace a rimmed baking sheet on bottom rack of oven; preheat to 450°. Toss brussels sprouts and oil in a large bowl; season with salt and black pepper.
Carefully remove baking sheet from oven. Arrange brussels cut side down on baking sheet. Roast brussels on bottom rack until softened and deeply browned, 20–25 minutes.
Meanwhile, bring honey to a simmer in a small saucepan over medium-high heat. Reduce heat to medium-low and cook, stirring often, until honey is a deep amber color but not burnt, 3–4 minutes.
Remove from heat and add vinegar and red pepper flakes and whisk until sauce is smooth. Return saucepan to medium heat, add butter and ½ tsp. salt, and cook, whisking constantly, until glaze is glossy, bubbling, and slightly thickened, 3–4 minutes.
Transfer brussels sprouts to a large bowl. Add glaze and scallions and toss to combine. Transfer to a platter and top with lemon zest.