Adjust the oven rack to the second position inches from the top (about 6-8 inches from the flame) and preheat the broiler on high. Spread the cherry tomatoes, onion and garlic on a small sheet pan and drizzle with 1 tablespoon olive oil. Place the sheet pan in the oven and broil until the vegetables achieve a subtle char, about 7-9 minutes. Every broiler is slightly different, so keep an eye on them and turn the baking sheet as needed. Remove from oven and set aside to cool slightly.
