Rockin' Oysters Rockefeller — osselect

Ingredients

• 12 fresh oysters
• 1/4 cup beer
• 1/2 clove garlic
• seasoned salt to taste
• 1-3/4 black peppercorns
• 2 tablespoons butter
• 1/4 onion, chopped
• 1/4 clove garlic, crushed
• 1/4 package frozen chopped spinach, thawed and drained
• 50g Monterey Jack cheese, shredded
• 50g fontina cheese, shredded
• 50g mozzarella cheese, shredded
• 2 tablespoons milk
• 1/2 teaspoon salt, or to taste
• 1/4 teaspoon ground black pepper
• 1-1/2 teaspoons fine bread crumbs