Preheat oven to 350 F degrees F. Line an 8 inch metal pan with foil and grease the bottom.

Mix together the flour, baking powder and salt; set aside.

Melt butter in a large saucepan set over medium heat. Add the brown sugar to the warm butter. Remove from heat and let the mixture cool for 5 minutes before beating in the egg.

With a spoon or whisk, gently beat in the egg, vanilla and rum. Stir dry ingredients into batter. Let the batter cool down if it is still warm, then stir in the chips and nuts.

Spread in pan and bake for about 35 minutes or until pale golden and edges start to pull away from the sides,

Let cool completely, then lift from pan and cut into squares.