- 1 1/2 (1 ounce) squares unsweetened chocolate
- 1/4 cup butter
- 1 1/2 cups confectioners' sugar
- 1 egg white
- 1 teaspoon vanilla extract
- Melt chocolate and butter in small heavy saucepan over low heat; stir to blend.
- Beat in powdered sugar. Beat in egg white and vanilla, adding a little water, if necessary, to make smooth, slightly soft frosting. Spoon over Chocolate Frosted Marshmallow Cookies cookies to cover marshmallows.