Heat oven to 350°F. Grease 8-inch square (2-quart) glass baking dish with cooking spray or shortening. In medium bowl, stir together flour, granulated sugar, hazelnuts, 2 tablespoons cocoa and the baking powder. Stir in milk, 1/4 cup liqueur and the oil. Spread batter in pan.
Sprinkle batter with brown sugar and 1/4 cup cocoa. Pour boiling water over batter.
Bake 40 to 45 minutes or until center is set. Cool 20 minutes before serving.
Meanwhile, in chilled small bowl, beat cream ingredients with electric mixer on high speed until stiff peaks form.
To serve, spoon warm pudding cake into individual dessert bowls; spoon pudding over cake. Top with whipped cream.