01 -
Turn oven on to 350°F (175°C). Put parchment paper in a 9x13 inch baking dish with extra hanging over the sides so you can lift it out easily later, or just use cooking spray.
02 -
Combine 2 tablespoons sugar with 2 teaspoons cinnamon in a small dish and put it aside for now.
03 -
Beat the soft butter with 2 cups sugar in a big bowl until it's fluffy and pale, taking about 2-3 minutes.
04 -
Add eggs one by one, then mix in the vanilla extract.
05 -
In another bowl, stir together flour, cream of tartar, baking soda, and salt.
06 -
Slowly add your dry mix to your butter mix, stirring just enough to blend it all. You'll end up with thick dough.
07 -
Push the dough flat across your baking dish. It's pretty sticky, so try using a bit of water on your hands or a spatula to make it easier.
08 -
Scatter your cinnamon-sugar mix all over the top of the dough.
09 -
Stick it in the hot oven for 25-30 minutes. You'll know it's done when the sides turn slightly golden and a toothpick comes out with just a few crumbs stuck to it. Don't leave it in too long if you want them chewy.
10 -
Let everything cool down completely in the dish on a wire rack before you cut it into squares.