Preheat the over to 350 degrees Fahrenheit. Spray an 8-inch square pan lightly with vegetable spray and line the pan with two cris-crossing pieces of parchment paper, leaving an overhang. Add the sugar and cinnamon to a small bowl until combined and set aside. In a medium bowl, whisk together flour, baking powder, salt, and ground cinnamon until combined. Set aside. In a bowl of an electric mixer fitted with a paddle attachment, cream butter and sugar until light and fluffy, about 3-5 minutes. Add eggs one at a time, beating well after each addition. Add in the vanilla bean paste. Reduce the mixer speed to low and add in the flour mixture, alternating with the buttermilk, starting and ending with the flour. Mix until just combined. Remove the bowl from the mixer. Give it a couple of folds to combine. Sprinkle half the cinnamon sugar mixture on the prepared pan. Pour the cake batter over the cinnamon sugar mixture and even out using an offset spatula. Sprinkle remaining cinnamon sugar mixture over the batter. Place in the oven and bake for 25-32 minutes, or until a toothpick inserted in the center of the cake comes out clean. Remove cake from oven and allow to cool for 5-10 minutes, then invert it onto a plate or wire rack to cool completely. Once cool, cut into squares. Makes about 16 snack cake squares.