Melt butter in the microwave. Combine melted butter, sugar, vanilla, and salt in the jug. Blend eggs and add to the sugar mixture.
Add cocoa, flour and nuts. Mix well and then spread mixture in the Heat N Eat Shallow Container; seal with vent open and microwave on medium high for 5-7 minutes.
Using a paper towel dry off the seal and reseal. Let stand 5 minutes, cut and serve.