Melt 1/2 stick of butter in a large skillet. Whisk in 1 package (or 5 Tbs) of Seafood Pasta seasoning and 1.5 cups of milk. Simmer for 5-7 minutes until sauce thickens. Add 1 lb of peeled and deveined shrimp and cook until just pink, about 4 minutes. Serve hot over pasta and garnish with green onions.