Preheat your oven to 350°F (175°C). Line two large baking sheets with parchment paper or silicone baking mats.
In a large mixing bowl, beat the softened butter for about 1 minute until smooth and creamy. This aerates the fat for a better crumb.
Add the eggs, extra egg yolk, vanilla extract, and vegetable oil. Beat until well combined, ensuring ingredients are at room temperature to prevent seizing.
Pour the dry cake mix and baking powder into the wet mixture. Fold gently with a spatula until just combined. Do not overmix.
Place the bowl in the refrigerator for 15 minutes. Chilling slows down spreading in the oven.
Using a medium cookie scoop, portion out the dough and roll into smooth balls. Roll in powdered sugar if a crinkle effect is desired.
Bake for 9-11 minutes until the edges are set but the centers are still soft.
Let sit on the baking sheet for 5 minutes before transferring to a wire cooling rack to cool completely.
