Make It
Step 1
Preheat oven to 300° F. Line 10 x 8-inch baking pan with parchment paper.
Step 2
Microwave butter and morsels in a medium, microwave-safe bowl at HIGH (100%) power for 1 minute; stir. Microwave at additional 10- to 15-second intervals, stirring until smooth. Let cool.
Step 3
Beat eggs and sweetened condensed milk in large mixer bowl. Beat in chocolate mixture. Add flour; mix well. Pour batter into prepared baking pan.
Step 4
Bake for 30 to 35 minutes. Cool completely in pan on a wire rack.
