Camarones al Ajillo (Garlic Shrimp)

INGREDIENTS

• 1 tablespoon olive oil
• 1/4 cup butter
• 1/2 green bell pepper, sliced
• 1 large onion, sliced
• 10 cloves garlic, pressed
• 1 pound fresh large shrimp, shelled and deveined
• 1/2 cup tomato sauce
• 1 tablespoon dried parsley
• 1/4 teaspoon crushed red pepper flakes (optional)
• salt and ground black pepper to taste