1Cook the butter and brown sugar over low heat, in a sauce pan, until it comes to a boil. Remove from heat and let cool.
2Preheat oven to 350 degrees F (175 degrees C). Grease a 12x18 inch jelly roll pan.
3In a medium bowl, stir together the butter mixture, and the eggs and vanilla. Sift together the flour, baking powder, salt, and cinnamon; stir into the egg mixture until well blended. Then stir in pecans. Spread the batter onto the prepared jelly roll pan. Bake in the preheated oven for 25 minutes. Immediately sprinkle chocolate chips over the whole sheet. Let stand for 5 minutes, then spread chocolate evenly over the entire surface. Cut into squares.