Preheat oven to 350° and grease a 9x9 pan (spray, butter)
In a large mixing bowl, mix the butter at room temperature and brown sugar.
Add in the eggs and vanilla then mix until uniform consistency.
Add the flour, baking powder, and salt and stir until well incorporated. Once again mixed to a uniform consistency, add in Dulcey Feves to your liking.
Pour the batter into the prepared pan and smooth out.
Place in the oven to bake for 30 minutes until edges are golden and toothpick comes out mostly clean. Allow to cool completely, then cut into squares.