Preheat the oven to 350 degrees F. Spray 9x13-inch pan with nonstick spray. Line the pan with parchment and let it hang over the sides. Spray the parchment with nonstick spray too.
In a medium bowl, whisk together the flour, baking powder, cinnamon, salt, cream of tartar and nutmeg; set aside.
In a large bowl, use an electric mixer to combine the butter and brown sugar (3 to 5 minutes). Mix in the eggs, one at a time, and then the vanilla. Keep beating until the mixture is smooth.
Stir in the flour mixture until well blended. If using cinnamon chips, stir them in now. The batter will be thick. Spread it evenly into the prepared pan. Spray your hands with cooking spray and use them to pat the mixture down evenly.
ADD THE TOPPING AND BAKE:
Combine the topping ingredients in a small bowl; sprinkle evenly on top of batter. Bake 25 to 30 minutes or until the surface of the blondies springs back when gently pressed. Let the pan cool completely.
CUTTING AND ADDING OPTIONAL GLAZE:
When ready to cut, use the ends of the parchment paper to lift out the baked bars. Place it on a cutting board. If you’re adding the glaze, whisk the glaze ingredients in a medium bowl and drizzle onto the bars in a decorative fashion. Let the glaze set (this will work more quickly in the refrigerator) and then use a large, sharp knife to cut into bars.
Notes
Nutritional information does not include cinnamon chips or glaze.
You don't have to use parchment paper in your pan if you don't have any. You can always just bake them in the pan and then cut them and lift them out. Baking w/ parchment though will help you to get the cleaner cuts seen in the photograph because you can take the whole thing out of the pan and work directly on a cutting board.
This is a very sweet treat. Leave off the glaze if you wish, but it adds a good flavor to the top (and you can get a nice design out of it). Put the glaze in a little zip bag, snip off the end and you'll have a way to squirt the glaze on in whatever decorative way you'd like.
If you have chunky, white, sparkling sugar, add that to the top too for extra sparkle.