Preheat the oven to 400 degrees F. Wash the veggies then slice the tomatoes in half lengthwise, peel and cut the carrots in half and peel and cut the onions into large chunks. Arrange the vegetables in a single layer on a baking sheet. Then place 3-4 cloves a garlic around them. Drizzle with olive oil and then season with salt and pepper. Roast the veggies at 400 degrees F for 40-45 minutes.
Take the roasted veggies out of the oven. *If using a traditional blender, place the vegetables into the blender with 2 cups of broth and blend until smooth. Then transfer to a dutch oven or pot on the stove. *If using an immersion blender, place the vegetables into a dutch oven or large pot on the stove and add 2 cups of both. Then use the immersion blender to blend until smooth.
Place the soup pot on the burner on a low heat. Add in butter and a squeeze of lemon juice and stir to combine. Then add basil and parsley. Stir to warm through and remove from the heat. Ladle into bowls and top with a drizzle of heavy cream if desired. Serve hot and enjoy!