Preheat the oven to 350 degrees. Spray a 9 x 13 pan with cooking spray and set aside.
In a large bowl, cream the butter and sugar and brown sugar together until light and fluffy.
Add in the eggs, one at a time, thoroughly beating the mixture in between each egg.
Add in the vanilla and mix.
Add in the flour, cream of tartar, salt and baking soda and mix until the dough is combined, stopping to scrape the sides of the bowl.
Stir in ½ c of the cinnamon chips.
Scoop about ⅔ of the dough and press it in an even layer in the bottom of the pan.
In a small bowl, whisk the sugar and cinnamon together and sprinkle in an even layer over the bottom layer of dough.
Take the remaining dough and drop small scoops over the top of the cinnamon/sugar, and gently press to create a top layer of dough. (This will take a few minutes as the dough is sticky, but it doesn’t have to be perfect!)
Place the pan in the oven and bake for 25-30 minutes, until the top is golden.
Remove and immediately sprinkle the remaining cinnamon chips over the top to slightly melt into the top crust. Let the bars completely finish cooling.
To make the glaze, whisk the powdered sugar, vanilla and 1 tablespoon of cream together, adding the additional cream if necessary to make the glaze thinner. Drizzle the glaze over the top of the bars. Slice and enjoy!
Store any leftovers in an airtight container for up to 3 days.