1 (16 ounce) package cream cheese, softened
1 cup butter, softened
1 egg
1 1/2 cups milk, room temperature
1/4 teaspoon vanilla extract
1/4 cup milk
1/4 teaspoon cream of tartar
Preheat oven to 350 degrees F (175 degrees C).
Place cream cheese and butter in shallow dish or bowl. Heat milk in microwave oven until boiling. Stir egg into milk mixture.
Beat cream of tartar until mixture resembles coarse crumbs. Spread cream mixture on bottom of muffin.
Bake in preheated oven for 15 minutes.