Preheat oven to 350°F. Line two baking sheets with parchment.
Whisk the oil, beaten eggs, and vanilla in a large bowl until smooth.
Add the cake mix and stir just until a soft dough forms; do not overmix.
Fold in sprinkles and, if using, white chocolate chips until evenly distributed.
Scoop heaping tablespoons of dough onto sheets, spacing about 2 inches apart.
Bake 9–11 minutes, until edges are set and centers look slightly soft.
Cool on the sheet 5 minutes, then move cookies to a rack to finish cooling.