Simple pleasure - brownies

1 stick butter
1/2 cup cocoa powder
1 cup sugar
2 eggs
1 tsp vanilla
1/4 tsp salt
1/2 cup unbleached flour

Preheat oven to 350 degrees.
Melt butter in a large bowl in microwave. Add 1/2 c. cocoa, stir until smooth. Add sugar. Add eggs one at a time, stirring well after each adition. Add 1 tsp. vanilla, 1/4 tsp salt and flour, stir well. Pour into buttered 8x8 inch square pan. Bake for 20-25 minutes.