1/2 onion, finely chopped
2 garlic cloves, very thinly sliced
1 cup tomato puree
¼ tsp. oregano
¼ tsp. crushed red pepper flakes
2 tablespoons olive oil, divided
1 small eggplant, such as Italian or Chinese
1 zucchini
1 yellow squash
1 long red bell pepper
Few sprigs fresh thyme
Salt and pepper