Preheat oven to 350 degrees. Grease a 9-inch square baking pan.

In a large bowl, combine flour, cocoa, and salt, cinnamon and cayenne.

Melt butter in a large saucepan and remove from heat. Stir in sugar and vanilla. Quickly whisk in eggs, one at a time.

Add butter mixture to flour mixture and stir until well blended. Spread brownie batter into prepared pan and bake for 25-30 minutes. Cool completely before cutting into squares.