Preheat oven to 350° Fahrenheit.
Melt the chocolate and butter in a double boiler or in the microwave. Let cool for 5 minutes.
Meanwhile, place the eggs, sugar, baking powder, salt, flour, and both extracts into a large bowl. Add the melted and slightly cooled chocolate and mix until very well combined. Set aside 1/2 cup batter.
Add the pecans and pour into a well greased 9×13 pan and bake for 10 minutes.
Cream the cream cheese, butter and sugar in the bowl of an electric mixer and slowly add the remaining ingredients. Pour over the baked brownie bottom.
Swirl the reserved cup of chocolate batter into the top and marbleize it by running a knife gently through the top.
Bake for 45 minutes.