Ingredients:

  • 3 lbs fresh Roma or vine-ripened tomatoes, halved
  • 1 large yellow onion, thickly sliced
  • 6 cloves garlic
  • 3 tbsp extra virgin olive oil
  • 1 tsp sea salt
  • 1/2 tsp cracked black pepper
  • 2 cups vegetable or chicken broth
  • 1/2 cup fresh basil leaves, packed
  • 4 tbsp unsalted butter, cold and cubed
  • 1 tsp balsamic vinegar

Instructions:

  1. Preheat oven to 400°F (200°C). On a large rimmed baking sheet, toss halved tomatoes, sliced onions, and whole garlic cloves with olive oil, sea salt, and black pepper.
  2. Arrange tomatoes skin-side up and roast for 25 minutes until skins are slightly charred and onions are caramelized.
  3. Transfer the entire contents of the baking sheet, including all juices and charred bits, into a high-speed blender or large stock pot.
  4. Add the broth and fresh basil. Blend on high until completely smooth. If using an immersion blender, bring to a simmer in the pot before blending.
  5. While the soup is hot, gradually add the cold, cubed butter one piece at a time while blending to create a permanent emulsion. Stir in balsamic vinegar and serve immediately.