Preheat your oven to 450°F. Place the tomatoes (large ones halved), onion quarters, and garlic cloves on a sheet pan. Drizzle with olive oil, then sprinkle with salt and pepper. Toss to coat. Roast in the oven for 30 minutes, or until the tomatoes are soft and slightly charred. Make sure to check on it about halfway through and stir or turn over veggies if needed.
Blend the Soup:
Carefully transfer the roasted vegetables to a blender or food processor and blend until desired smoothness is reached. Transfer to a pot on the stove and over medium heat add broth, heavy whipping cream, Italian seasoning, garlic powder and more salt and pepper if needed.
Make the Grilled Cheese:
While the soup is roasting, spread butter on each slice of bread, or I like to just put the butter right in my pan and lay the bread in it. Lay bread in the pan and once one side is slightly golden, layer your cheese and bread on top of one piece to make your sandwich. Cook until golden brown on both sides and cheese is melted.