Preheat the oven to 350 degree. Place the raisins and 1/2 cup of rum in a saucepan over low heat and simmer until almost all of the rum has been absorbed. Set aside to cool.
Place the butter and chocolate in the saucepan over low heat and stir until smooth.
Place the chocolate mixture in a bowl and add sugar, eggs, flour, cocoa, baking powder and raisins and mix until combined.
Pour the mixture into a 8 inch square cake pan that has been grease and floured. Bake for 50-60 minutes or until set. Drizzle or brush the remaining 2 tablespoons of rum onto the brownies. Cool completely before cutting into squares.
Note: Recipe is adapted from Flavour cookbook authored by Donna Hay