Line a 13×9 glass baking dish or baking pan with parchment paper.
Set it to the side.
In a large bowl, add the melted butter, sugar, and milk.
Stir to combine.
Add in the eggs one at a time, stir until combined after each egg is added.
In a separate large bowl, add the flour, baking powder, cream of tartar and salt.
Stir to combine.
Add the butter mixture into the flour mixture stir until combined.
Pour the batter into your 13×9 pan.
In a small bowl, add the 2 Tablespoons sugar and 1½ teaspoons cinnamon.
Stir to combine.
Sprinkle the topping over the batter.
Bake for 25-28 minutes.
Once removed from the oven let it cool to room temperature before cutting.
Notes
Make sure your eggs are room temperature. This makes it so much easier to incorporate everything into a smoother batter. Allow the melted butter to cool before adding it in to the mix for the same reason. You don’t want hot butter to scramble the eggs!
If you don’t have cream of tartar you can use white vinegar or fresh lemon juice to replace it. For this particular snickerdoodle blondie recipe, use 1 teaspoon of either one of these substitutes. It’s as simple as that and you won’t even notice the difference!
I’m thinking you could add more of a crunchy topping to these bars, if you want to jazz them up a bit. Maybe crushed walnuts and other ingredients to create a typical “streusel” topping? The choice is up to you!