1. Preheat the oven to 350ºF. In a large saucepan, melt the butter. Add the sliced onion and smashed garlic and cook over medium heat, stirring occasionally, until softened, about 5 minutes. Add the cocktail tomatoes and cook until they burst, about 8-10 minutes.
2. Add in the miso, brown sugar, crushed red pepper flakes, 1 tsp Kosher salt, and black pepper. Stir to combine. Add water (or stock, if using) and bring the mixture to a boil over high heat, breaking up any remaining intact tomatoes with the back of a spoon. Reduce the heat to medium-low, and simmer for 10 minutes.
3. Meanwhile, place the sourdough pieces on a lined baking sheet and drizzle with olive oil. Toss well to combine. Season with remaining ½ tsp Kosher salt and bake for 10 minutes. Add parmesan and toss well to combine. Allow to finish baking until golden brown. Remove from the oven and sprinkle with Togarashi, set aside.
4. Working in batches, transfer the tomato soup mixture to a blender and purée until smooth. Return the soup to a clean pot and re-warm the soup over low heat, if necessary. Ladle the soup into bowls and serve topped with the croutons.

Recipe Courtesy of Sunset