Preheat the oven to 350°F (175°C). Grease a 9x13 inch baking pan or line it with parchment paper.
In a large bowl, cream together the softened butter and 1.5 cups sugar until light and fluffy.
Beat in the eggs one at a time, then stir in the vanilla extract.
In a separate bowl, combine the flour, baking powder, salt, and 1 teaspoon cinnamon.
Gradually blend the dry ingredients into the creamed mixture until just combined.
Spread the dough evenly into the prepared baking pan.
In a small bowl, mix 2 tablespoons sugar with the remaining 1 teaspoon cinnamon, then sprinkle over the dough.
Bake for 25-30 minutes in the preheated oven, or until the center is set and the edges begin to pull away from the sides of the pan.
Allow to cool before cutting into bars.