Preheat the oven to 350°F
Slice the tomatoes in half and peel and cut the garlic cloves in half. Drizzle a little olive oil onto the baking sheet, lay out the tomato halves, and scatter on the garlic cloves and a pinch of salt and pepper. Place the tray into the oven and bake for 15-20 minutes.
In the meantime, heat a large pot over medium heat. Add the rest of the olive oil and saute the onions, celery, and carrots for 5 minutes until softened.
Add the tomatoes, garlic, spices, salt and pepper, and chicken stock, and simmer for 20 minutes.