Thaw, drain oysters. Combine butter, onions, celery, salt and pepper, garlic juice, lemon juice and parsley in 1 1/2 quart casserole. Cover. Microwave on High (100%) 4 minutes. Place oysters in small bowl. Cover. Microwave on High (100%) 2 1/2 minutes until edges curl. Drain. Add oysters, milk and 1 1/2 cups Ritz crackers to vegetables. Mix well. Combine 1/2 cup cracker crumbs with cheese and sprinkle over casserole. Microwave 4 minutes uncovered or until mixture is hot.