Position a rack in the center of the oven and heat the oven to 350 degrees F. Spray and flour a 9 x 13-inch baking pan, set aside.
In a large bowl, whisk together the cake flour, baking powder, baking soda, salt, and sprinkles.
In a smaller bowl or large glass measuring cup, whisk together the sugar, buttermilk, whole milk, vegetable oil, eggs, and vanilla extract.
Pour the wet ingredients into the dry and whisk to combine.
Bake, rotating the pan halfway through baking, until a toothpick inserted in the center of the cake comes out clean or with a few crumbs clinging to it, 25-30 minutes.
Transfer the pan to a rack to cool completely before frosting or storing. Cake can be stored wrapped at room temperature for up to three days.