1 large garlic clove, minced
1 teaspoon red pepper flakes
2 cups fresh whole basil leaves (one 2-ounce bag)
1/2 teaspoon dried thyme
Preheat the oven to 400°F.
Arrange the cut tomatoes on a large (10×16-inch) baking sheet. Drizzle the tomatoes with 1/4 cup olive oil and sprinkle with salt. Toss with your hands until the tomatoes are evenly coated with oil, then arrange them cut side up; they should fill the pan completely. Place in oven and roast the tomatoes for 50 minutes. Remove pan from the oven and set aside.
Warm the rest of the olive oil in a large saucepan over medium heat. Add the onion and sauté until soft and slightly golden, about 10 minutes. Add garlic and pepper flakes and sauté for one more minute. Carefully pour in all the tomatoes and their juices. Add the basil, thyme, and 1 cup water (you may need to add an extra cup if the tomatoes are on the dry side). Simmer for 15 minutes. Remove from heat and allow to cool slightly.
Blend the soup in batches in the blender, pouring finished soup into a clean saucepan or soup tureen (you may wish to strain the soup as you do this to remove any remaining skin or seeds, depending on the strength of your blender).
Serve piping hot, with crackers or chunks of store-bought artisan-style bread.