Place tomatoes on a parchment paper lined baking sheet, cut side up.
Place onion on the baking sheet as well.
Cut the top off the garlic bulb and place it on a small square of aluminum foil.
Drizzle the tomatoes, onion, and garlic bulb with olive oil. Sprinkle with salt and pepper. Wrap the garlic bulb tightly in the aluminum foil.
Roast the vegetables in the oven for 25-30 minutes, until they are soft and turning brown on top.
Add roasted vegetables to a blender. Add fresh basil to the blender as well. Blend the ingredients until smooth.
Pour the blended mixture into a soup pot. Whisk in the chicken broth and bring just to a boil over medium heat. When bubbling, turn the heat down to low, with the lid off, and simmer for 15 minutes.
Whisk in the heavy cream and simmer for 5 minutes more.
Ladle into soup bowls and garnish with fresh basil if desired. Enjoy!
Notes
Use Ripe Tomatoes: The better your tomatoes, the better your soup.
Even Roasting: Cut the tomatoes and onion in similar sizes so they cook evenly.
Blending: If you like a chunkier texture, don't blend the soup as much. For a velvety smooth texture, blend longer. You can also strain the soup to remove any tomato skins that don't blend up.
Store Properly: If you have leftovers (lucky you!), store the soup in an airtight container in the fridge. It will keep for up to 3 days and makes a great quick meal.