1/2 cup milk
1/3 cup white vinegar
a pinch garlic powder
3 tablespoons butter, divided
In a large bowl, mix milk, vinegar, garlic powder and 1 tablespoon butter. Add to the cream cheese mixture, stirring just to moisten.
With a sharp knife or metal spatula, seal and cut a large piece out of the cream cheese mixture. Mix this around the shrimp or mussels and serve.