I'm not sure this is exactly what you're looking for, but hope it will help. I am going to post the recipe as I've made it (with semi-sweet chocolate chips) but I don't know why you couldnt' make it with white chips instead? It's so easy, it would be worth trying.

Microwave Meltaway Fudge

1 (14-ounce) can sweetened condensed milk (not evaporated)
1 (12-ounce) package (2 cups) semi-sweet chocolate chips
1 teaspoon vanilla

Line 8-inch pan with foil so foil extends over sides of pan; butter foil. In 2 1/2 quart microwave safe bowl, combine condensed milk and chips. Microwave on HIGH for 1 1/2 to 1 3/4 minutes or until melted, stirring once during cooking. Stir until smooth. Add vanilla; stir well. Pour into buttered, foil-lined pan. Refrigerate until set.

Remove fudge from pan by lifting foil; remove foil from sides of fudge. Using large knife, cut fudge into squares. Store in airtight container in refrigerator.