Roasting tomatoes concentrates the bright sweetness of the ripe fruit. You can use roasted tomatoes in place of fresh tomatoes in nearly any recipe for added richness, or in recipes that call for canned "fire-roasted" tomatoes.
Choose ripe, flavorful tomatoes for oven roasting. Plum tomatoes are a great choice since they have more flesh and less “water” than other varieties, but you will get excellent results from virtually any variety, including cherry or grape tomatoes.
First, wash the tomatoes well. Cut the core out of larger tomatoes before slicing them or cutting them into wedges. Smaller varieties, like cherry tomatoes, need only to be cut in half.
Arrange the tomatoes on an oiled baking sheet. Turn the tomatoes so they are lightly coated with the oil, then put them into a 350°F oven until they darken in color and have a sweet, rich aroma. Larger tomato slices or wedges may take up to 30 minutes, thin slices or small tomatoes will take 15 to 20 minutes.
If you want to add even more flavor, season the tomatoes before you put them into the oven with salt, pepper, minced garlic, or chopped herbs.