It's dinner time!

Ingredients

• 1 head cauliflower
• 1 sweet onion (such as Vidalia®), thinly sliced
• 1 cup grated mozzarella cheese
• 1 cup grated Monterey Jack cheese
• ¾ cup grated Gouda cheese
• ¼ teaspoon cayenne pepper
• salt and ground black pepper to taste
• 1 cup milk
• ½ cup bread crumbs, or as needed