Preheat oven to 350 degrees. Prepare a 9-inch square baking pan by buttering the bottom and then using two pieces of parchment criss-crossed over the bottom and up over the sides.

Chop the semi-sweet chocolate into small chunks. Reserve ¼ cup to sprinkle over the top of the brownies. In a double boiler, melt the butter and the chocolate over simmering water.

Meanwhile, in a bowl, combine flour, cocoa powder, baking powder and salt. Use a whisk to combine the dry ingredients well.

When the butter and chocolate are melted, remove them from heat and stir in the sugar.

Lightly beat 2 eggs in a bowl and then mix them into the bowl along with the vanilla extract.

Stir the dry ingredients into the wet ingredients using a rubber spatula or spoon mixing just until incorporated. Do not over mix or use an electric mixer!

To prepare the cream cheese mixture, mix softened cream cheese with 1/3 cup sugar. Add the egg and mix well.

Put dollops of brownie mixture in the pan and follow with spoonfuls of cream cheese mixture. Use a knife, moving it back and forth to swirl the two mixtures.

Sprinkle reserved chocolate pieces on top.

Bake in the oven for 40-45 minutes or until a toothpick inserted comes out with moist crumbs. It should not be dry.

Cool in the pan for 15 minutes. Use the overhanging parchment to remove the brownies and let cool completely before cutting.

Run a large knife under hot water and cut brownies into 16-inch squares.