Cheesy Spam Puff

Ingredients

• 5 slices white bread, torn into small pieces
• 1 1/4 cups milk or 1 1/4 cups half-and-half cream
• 3 eggs
• 1 tablespoon spicy mustard
• 1/2 teaspoon garlic powder
• 1/2 teaspoon paprika
• 1 (12 ounce) can Spam, cubed
• 2 cups grated cheddar cheese, divided
• 1/2 cup chopped onion
• 1/2 cup grated monterey jack cheese