• Preheat your oven to 350° F.
• Spray the bottom of a 13"x9" baking pan with baking spray and line with a parchment sling.

Make the batter

• Add flour, baking powder and salt to a bowl and whisk until combined.
  292 g all-purpose flour, 1 ¼ teaspoon baking powder, ½ teaspoon salt
• Either with an electric mixer or in the bowl of a stand mixer with the paddle attachment, beat butter on high speed for about 2-3 minutes, until creamy and light in color. Add in both sugars and beat well.
  170 g butter, room temperature, 250 g sugar, 100 g brown sugar
• Beat in the eggs one at a time, and then beat in the vanilla extract.
  3 eggs, 1 teaspoon vanilla extract
• Add the dry ingredients a little at a time into the butter mixture, until everything is incorporated.

Add the toppings

• Add half of the batter to the prepared baking pan and smooth out across the bottom of the pan.
• Mix together the cinnamon and sugar, and sprinkle evenly all over the batter in the pan.
  1 tablespoon sugar, 1 tablespoon cinnamon
• Spoon the rest of the batter on top of the cinnamon layer so that parts of the cinnamon show through.

Bake

• Bake for 20 to 25 minutes. A toothpick should come out clean, or the internal temperature should read 205° F.
• After the bars are completely cool, cut into squares. *Note: you can also glaze first and then cut the bars.

Glaze

• Mix the powdered sugar, vanilla and 1 tablespoon of the milk or cream. Add more milk or cream depending on how thick you would like the glaze to be.
  125 g powdered sugar, 1-2 tablespoon milk or heavy cream, ¼ teaspoon vanilla extract
• Drizzle the glaze over top of the bars and serve.
• Store in an airtight container at room temperature for about 2-3 days, or freeze. For best freshness, wrap each individual bar.