1. In an 8- to 10-inch frying pan over medium heat, stir garlic and onion in olive oil until golden brown, about 2 minutes.
2. Add shrimp and sake. Stir often until shrimp are opaque but still moist-looking in center of thickest part (cut to test), 2 to 3 minutes.
3. Add butter, soy sauce, and parsley; stir until butter is melted and blended into sauce.
4. Spoon into 4 small shallow bowls. Serve with crusty bread or hot cooked rice.