¼ cup unsalted butter, 2 teaspoons vanilla extract, ½ cup sugar
Cream your sugar, softened butter, and vanilla extract together with a hand or stand mixer with a paddle attachment.
1 large egg, ½ teaspoon cream of tartar, 1 ¼ cup all purpose flour, ½ teaspoon baking soda, ¼ teaspoon salt, ½ cup sourdough starter
Add the other ingredients and mix until just combined.
Roll the dough into small balls (about 1 ½ to 2 teaspoons of dough). Place on a parchment lined (not wax paper) or well greased baking sheet with room to spread. Press them down slightly.
Bake 7 to 9 minutes or until the edges are golden brown. Let rest for 5 minutes on the sheet before transferring to a cooling rack.
Notes
Any nutritional information is an estimate by online calculators. Please verify using your own data.Storage: Store any leftovers in an airtight container at room temperature. The cookies will be fresh for up to four days after baking.