Preheat the oven: Set to 350°F (175°C).
Line two baking sheets with parchment paper or silicone mats.
Mix the wet ingredients: In a large bowl, whisk the eggs and oil until smooth and glossy.
Add the cake mix: Pour the dry cake mix into the bowl. Stir with a spatula until no dry pockets remain. The dough will be thick and sticky—this is normal.
Fold in extras (optional): If using chips, nuts, or sprinkles, gently fold them in now.
Keep total mix-ins to about 1 cup so the dough stays cohesive.
Scoop the dough: Use a tablespoon or a small cookie scoop to portion 1 to 1.5-tablespoon mounds. Space them 2 inches apart on the baking sheets.
Shape if needed: For neater edges, lightly roll each scoop into a ball with your hands. Slightly flatten the tops for more even baking.
Bake: Bake for 9–11 minutes, until the edges are set and the tops look just dry.
Do not overbake; they firm up as they cool.
Cool: Let the cookies rest on the sheet for 2–3 minutes, then transfer to a wire rack to cool completely or enjoy warm.