Preheat oven to 350°F. Grease an 8x8 inch baking pan and line with parchment paper, leaving some overhang on the sides.
In a large bowl, whisk together the melted butter and 1 ½ cups sugar until combined.
Beat in the eggs one at a time, then stir in the vanilla.
In a separate bowl, whisk together the flour, baking powder, and salt.
Fold the dry ingredients into the wet ingredients until just combined.
In a small bowl, mix together the 2 tablespoons of sugar and cinnamon.
Spread the batter evenly into the prepared pan and sprinkle the cinnamon-sugar mixture on top.
Bake for 25-30 minutes, until the edges are set and the center is still slightly soft.
Allow to cool completely in the pan before lifting out and cutting into squares.
