Preheat oven to 450 degrees F.

Wash, core and cut the tomatoes into halves. Arrange the tomatoes, garlic cloves and onions onto a baking tray. Drizzle with olive oil and season with salt and pepper, and roast for 20 to 30 mins.

Place the tomatoes, garlic, and onion in a large pot. Add the chicken stock, water, and thyme. Bring to a boil and simmer for 15 mins. Remove from the heat and let it cool slightly; then discard thyme sprigs.

Puree soup in a blender until smooth. Return soup to low heat, add cream and adjust consistency, if necessary. Season with salt and pepper. Garnish in bowl with a splash of heavy cream.