Step 1: Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper or a silicone baking mat.
Step 2: In a large mixing bowl, using an electric mixer, beat together the softened cream cheese and softened butter until light and fluffy, about 2-3 minutes.
Step 3: Add the large egg and vanilla extract to the cream cheese mixture and beat until well combined.
Step 4: Gradually add the cake mix to the wet ingredients, mixing on low speed until just combined and a soft dough forms. Do not overmix.
Step 5: Place the 1 1/2 cups of powdered sugar in a shallow bowl. Scoop about 1 tablespoon of dough and roll it into a ball. Generously roll each dough ball in the powdered sugar until fully coated.
Step 6: Place the coated dough balls about 2 inches apart on the prepared baking sheet.
Step 7: Bake for 10-12 minutes, or until the edges are lightly golden and set, but the centers still look soft and slightly gooey. Do not overbake!
Step 8: Remove from the oven and let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely. The centers will set as they cool.