In a stand mixer (or large bowl with a hand mixer), cream together the cream cheese and butter until light and fluffy, about 1-2 minutes.
Slowly add in the powdered sugar until it is incorporated and smooth. Then, add in the egg, vanilla extract, and sourdough discard until fully combined.
Mix in the flour, salt and baking powder until there are no more dry bits of flour and a smooth dough has formed.
Cover and let rest in the fridge for 1-2 hours.
Preheat your oven to 375 degrees. In a small bowl, mix together the granulated sugar and cinnamon. Take ½ a tablespoon of cookie dough, roll it into a ball, and coat it with cinnamon sugar. Place each ball on your baking sheet 1-2 inches apart.
Bake for 9-10 minutes, but do not over-bake. The cookies might seem soft and slightly underdone, but they will finish setting up as they cool.
Transfer the cookies to a cooling rack and enjoy with a big glass of milk!
