Preheat oven to 350 degrees F. Grease an 8x8x2-inch baking pan; set aside. In a medium bowl stir together the flour, granulated sugar, 2 tablespoons cocoa powder, baking powder, and salt. Stir in the milk, oil, and vanilla. Stir in the pecans.
Pour the brownie batter into the prepared baking pan. In a small bowl stir together the brown sugar and ¼ cup cocoa powder. Add in the boiling water and then slowly pour this mixture over the batter.
Bake for 40 minutes. Remove from oven and place on wire rack to cool for 45 to 60 minutes. Serve this brownie pudding cake warm with a scoop of ice cream on top. Spoon the pudding mixture at the bottom of the cake over the top and garnish with extra chopped pecans if desired.