Peanut Butter Fudge

I'm in the mood for chocolate. And chocolate and peanut butter are an undeniably perfect combo (other than caramel and chocolate, yum!) So I stumbled upon this recipe on StumbleUpon.com, naturally. But the real credit goes here.

Ingredients:
2 cups peanut butter chips
1 cup semisweet chocolate chips
1/2 cup butter
1 (14 ounce) can sweetened condensed milk

Directions: 
1. Line a 9x9 inch square pan with wax paper.
2. In a medium sized saucepan, melt butter over medium heat. Stir in the condensed milk. Add the peanut butter and chocolate chips, stirring constantly until everything is melted and blended together.
3. Pour the mixture into the prepared pan and refrigerate for 3 hours. Cut into squares when cool.