Preheat oven to 350 degrees F (175 C). Grease 13x9 pan.
In a large bowl, mix softened butter and brown sugar together until creamy. If you have a mixer, just keep it in the cupboard for this recipe. I think you produce a more moist 'cookie-cake' if you mix it the old fashioned way! ?
Add eggs, one at a time, mixing well between each addition. Don't worry, it is supposed to be pretty thin.
Stir in vanilla.
In a small mixing bowl, stir flour, baking powder, and salt until well combined.
Slowly add flour mixture to the brown sugar mixture. It will get thick!
Finally, add chocolate chips and pecans (if using).
Dump (not pour since it's so thick) into prepared pan. Spread evenly around the pan with the back of your mixing spoon.
Bake for 30 minutes or until the top is a beautiful golden brown. Be careful not to overcook.
Let cool slightly. Cut. Serve. Enjoy!!