Set your oven to 350 degrees Fahrenheit. Line your pans with parchment paper. This prevents the cookies from sticking.

Sift the flour in a bowl. Add cream of tartar and baking soda. Add the salt and whisk it well. This keeps the dough light and airy.

Put butter and sugar in a mixer. Beat them until the mix looks fluffy. This usually takes about three to five minutes.

Add the eggs one at a time. Mix well after you add each egg. Scrape the sides of the bowl often.

Turn the mixer to a low speed. Slowly add the flour mixture to butter. Mix until just combined. Do not overmix the dough now.

Mix the extra sugar and cinnamon. Use a small bowl for this step. Stir it until the color is even.

Scoop small balls of dough. They should be about one inch wide. Roll them between your palms to smooth.

Drop each ball into the cinnamon sugar. Roll it around to coat it fully. Make sure every spot is covered well.

Put balls on the prepared pans. Leave two inches of space between them. They will spread out while baking.

Bake for 10 to 12 minutes. The edges should be set and golden. The centers will still look a bit soft.

Let them sit on the pan first. Move them to a rack after five minutes. Eat them warm or save for later!