Created on October 8th, 2007
Preheat oven to 350 degrees.
Line an 9x13 baking pan with foil. Grease with 1 tsp. Butter
In a large mixing bowl, beat together butter and sugar at medium high speed until mixture is light and fluffy, then add peanut butter and beat until blended well.
Beat in eggs, egg yolk and vanilla.
At low speed, add flour and salt mixing until just combined.
Stir in chocolate chips.
Spread batter into prepared baking pan. (this is should be a thick batter) Smooth top till all batter is level in pan.
Bake until brownies are golden, about 40 - 45 minutes.
Let cool completely before cutting.