Position a rack in the lower third of the oven and preheat the oven to 350 degrees Fahrenheit. Line 24 cupcake cups with paper liners.

In a large measuring cup or a small bowl, mix together the milk and vanilla; set aside.

In the bowl of a stand mixer fitted with the paddle attachment (or in a large mixing bowl, using a handheld mixer), combine both flours, sugar, baking powder, and salt and mix on low speed for two to three minutes until thoroughly combined.

With the mixer on low speed, add  cubed butter a few pieces at a time, mixing for about two minutes, until the mixture resembles coarse sand. With the mixer on medium speed, add the eggs one at a time, mixing well after each addition.

Turn the speed to low and gradually add the milk and vanilla, then mix for another one to two minutes. Remove the bowl from the mixer and, using a rubber spatula, incorporate any ingredients hiding at the bottom of the bowl, making sure the batter is completely mixed.

With a large ice cream scoop or spoon, scoop the batter into the prepared cupcake cups, filling each baking cup about two-thirds full. Bake for 20-25 minutes, until a cake tester inserted in the center of a cupcake comes out clean. Let cool for at least 20 minutes.

In the bowl of a stand mixer fitted with the paddle attachment (or in a large mixing bowl, using a handheld mixer), cream the butter on medium speed until light and fluffy, two to three minutes. Add four cups of the confectioners’ sugar, milk, and vanilla and mix on low speed until smooth and creamy, two to three minutes.

Gradually add up to three cups more sugar, mixing on low speed, until the frosting reaches the desired light and fluffy consistency, three to five minutes.

If desired, add a drop or two of food coloring to the frosting to tint it, mixing well; add more coloring as necessary until you reach the desired shade. If you want multiple colors, scoop the frosting into several bowls before adding the food coloring. 

The frosting can be stored in an airtight container at room temperature for up to two days.

Using a spatula or a butter knife, spread the tops of the cupcakes with swirls of frosting. Top with sprinkles, if desired. 

The cupcakes can be stored in an airtight container at room temperature for up to two days.