Heat butter in a large saucepan and add potatoes, broccoli, onion and garlic. Cook until onions are tender.
Add stock and bring to a gentle simmer and allow to cook, stirring occasionally for 45 mins to an hour or until potatoes are fully cooked.
Blitz with a stick blender until smooth and stir through cream and grated cheese. Season to taste with salt and pepper.
Meanwhile, for the croutons, chop bread into small cubes and drizzle with oil. Season with onion powder, salt and pepper and toss to coat evenly. Bake or air fry at 200℃ for 5-8 mins or until golden.
Serve soup with croutons and extra cream if desired.