Preheat the oven to 400°. For faster cleanup, cover a baking sheet with tin foil and spray with vegetable spray. Set aside.
Carefully core the stem out of the tomatoes and discard. Slice the tomatoes in half, crosswise. Remove the seeds from the tomatoes. Drizzle each tomato with one teaspoon of olive oil. Divide the garlic between the tomato halves and sprinkle a very small pinch of red pepper flakes onto each tomato.
Add 1 tablespoon of pesto to each tomato half and spread evenly over the tomato. Divide the breadcrumbs between the tomatoes and bake for 18-22 minutes or until tomatoes soften and breadcrumbs are lightly toasted. If breadcrumbs are browning too fast, gently rest a sheet of tin foil over the top to prevent further browning.
Transfer tomatoes to a serving dish. Can be eaten hot or at room temperature. (I prefer them warm).
Notes
These are best when they're made, but leftovers can be kept refrigerated for 2-3 days. Reheat in the microwave or a low oven (325° for 10 minutes).