1
Adjust racks to middle and top positions and preheat oven to 425 degrees. Bring garlic herb butter to room temperature. Wash and dry produce.
Trim green beans, if necessary. Halve, core, and thinly slice bell pepper into strips. Halve, peel, and cut onion into ½-inch-thick wedges; mince a few wedges until you have 1 TBSP (2 TBSP for 4 servings). Finely chop parsley.
Combine ¼ tsp garlic powder (½ tsp for 4) and ¼ tsp chili powder (½ tsp for 4) in a small bowl. (You’ll use the rest of the garlic powder and chili powder later.)