1
Adjust rack to top position (top and middle positions for 4 servings) and preheat oven to 425 degrees. Wash and dry produce.
Halve, peel, and thinly slice onion; mince a few slices until you have 1 TBSP (2 TBSP for 4). Halve, core, and thinly slice bell pepper into strips. Trim and finely dice cucumber. Dice tomato into ¼-inch pieces. Quarter lemon.