MAKE THE CROUTONS: Preheat the oven to 400 degrees.
In a large bowl, toss the bread, oil, salt and garlic powder until well combined.
Scatter the bread cubes, in a single layer, onto a half sheet pan.
Top each cube with a generous pinch of the shredded parmesan.
Bake until the bottoms are golden brown and the cheese is crisped, about 8 minutes.
PREPARE THE TOMATOES: Decrease the oven temperature to 375 degrees.
Spread the tomatoes onto a half sheet pan. Drizzle with the oil, season generously with the salt and toss to coat.
PREPARE THE SHALLOTS: Place the shallots in an even layer on a quarter sheet pan. Drizzle with the oil and season with salt.
PREPARE THE GARLIC: Trim off the top of the head of garlic to expose the cloves.
Place the garlic onto a sheet of aluminum foil and fold up the edges to create a cup.
Drizzle the oil over the garlic and season with salt.
Fold the foil to seal the garlic and place it onto the sheet pan with the tomatoes.
Place the tomatoes and shallot sheet pans into the oven. Roast the shallots until they begin to caramelize around the edges and are softened, about 20 minutes.
Roast the tomatoes until they are very wilted, for 50 to 60 minutes. By the time the tomatoes are done, the garlic will be, too.
MAKE THE SOUP Carefully squeeze the garlic into a blender pitcher. Add the tomatoes, shallots and vegetable broth. Cover and pulse until smooth.
Transfer to a medium saucepan and warm over medium heat, stirring often.
Season with salt and sugar, to taste.
To serve, ladle the soup into a shallow bowl. Top with a handful of croutons and finish with some freshly ground black pepper and a drizzle of extra-virgin olive oil.