Best Brownie Recipe

This photo contains brownies made by my young daughter.

The other day I went to make brownies and was amazed to find that I hadn't posted this recipe. For some reason, these turn out even better when made by my husband. Note that if you live above 6,000 ft. additional 1/4 - 1/3 c. of flour is crucial for this recipe. I should also note that I believe this recipe is originally from a Hershey's cocoa powder box.

1 c. butter (2 sticks)
2 c. sugar
2 t. vanilla
4 eggs
3/4 cocoa
1 c. flour (+ 1/4 - 1/3 c. for high altitude)
1/2 t. baking powder
1/4 t. salt
1 c. chopped nuts (optional)

In microwave safe bowl, melt butter (approximately 60-90 seconds). Stir in sugar and vanilla. Add eggs one at a time, beating well with a spoon after each addition. Add cocoa, beating until well blended. Add flour, baking powder and salt. Mix well. Pour into oiled 9x13 pan and bake for 30-35 minutes or until brownies begin to pull away from sides of pan. Cool completely prior to cutting.