Preheat oven to 350º.

In a bowl in the microwave melt the butter and set aside to cool.

In the bowl of an electric mixer beat the  egg and brown sugar until fluffy, about 3 minutes.  Beat in the vanilla and melted butter.

In a medium bowl whisk together flour, salt and baking powder. Add to mixer scraping down sides of the bowl as you go. Mix just until incorporated.  Fold in nuts and chocolate.

Spray an 8 x 8 inch pan and pour the batter.  Smooth the top with a spatula.  Bake in preheated oven for 25-30 minutes Until the tops are dry and golden and a toothpick comes out with a few moist crumbs. Cool completely before cutting.

May double recipe and bake in a 9 x 13 pan.

Bake 20-25 minutes.  Cut immediately.