Vesuvius Tomatoes - cooking recipe

Ingredients

3 tablespoons olive oil, divided
1 medium onion, finely chopped
6 ripe plum tomatoes, seeded and halved lengthwise
1 clove garlic, minced
2 teaspoons dried basil
1/2 teaspoon salt
1/4 teaspoon sugar
1/8 teaspoon crushed dried red pepper (or to taste)

Preparation

Preheat oven to 250 degrees F.
Heat 1 tablespoon olive oil in skillet over medium heat and saute onions until tender, about 8 minutes.
Place tomatoes in a single layer in large roasting pan, add onions, 2 more tablespoons olive oil, garlic, basil, salt, sugar and crushed red pepper.
Toss to coat thoroughly, and roast until tomatoes are tender but not mushy, about 2 hours.