1
Adjust rack to top position and preheat oven to 425 degrees. Wash and dry produce.
Trim and halve Brussels sprouts lengthwise. Halve, peel, and slice onion into 1-inch-thick wedges; mince a few slices until you have 1 TBSP (2 TBSP for 4 servings). Peel and mince or grate garlic.