Whisk cocoa, baking soda, cream of tartar, salt, and flour in a medium bowl. Set aside.

Cream butter and 3/4 cup granulated sugar in the bowl of a stand mixer fitted with the paddle attachment. Alternately, you can do this in a large bowl using a hand mixer. Mix in egg, vanilla, and instant coffee granules. Slowly add the dry ingredients to the wet and mix until combined.

Line 2 cookie sheets with silpat baking mats or parchment paper. Scoop 2 tablespoon balls of dough and place them on prepared cookie sheets. Chill for 30 minutes.

Note: You can also make the cookies 1 tablespoon size for smaller cookies. The baking time listed below will need to be adjusted.

Preheat oven to 350°F. Place remaining 1/3 cup granulated sugar and cinnamon in a small bowl and stir. Roll each cookie dough ball completely in the cinnamon sugar. Place back on baking sheets, 2” apart. Bake for 9-11 minutes. I like my cookies more on the underdone side, so I baked mine for 9 minutes, rotating the pans halfway through. If you like your cookies more done, bake them an additional 1-2 minutes.