Cereal Milk: To small bowl, add 1 cup cereal. Pour milk over top. Let stand for 20 to 25 minutes or until cereal is very soft. Strain mixture through fine-mesh sieve into bowl or measuring cup, pressing to release milk from cereal. Reserve cereal milk and discard cereal (you should have about 1 cup cereal milk).

Cupcakes: Preheat oven to 350°F. Line 16 muffin cups with paper liners.

In food processor, pulse 2 cups cereal until finely ground (makes about 3/4 cup).

In large bowl, whisk together ground cereal, flour, baking powder, baking soda and salt.

In small bowl, whisk together 3/4 cup cereal milk and sour cream.

In another large bowl, using handheld electric mixer on medium speed, beat together sugar and butter until light and fluffy. One at a time, beat in eggs, incorporating each fully before adding another. Beat in vanilla.

With mixer on low speed, alternately add flour mixture in 3 parts and sour cream mixture in 2 parts, starting and ending with flour mixture. Scrape bowl as needed between additions. Fold in sprinkles.

Spoon batter into prepared muffin cups, filling about three-quarters full.

Bake for 20 to 25 minutes or until tester comes out clean when inserted into center of cupcakes. Let cool completely on wire rack.

Frosting: In large bowl, using handheld electric mixer on medium speed, beat butter until light and fluffy. Reduce speed to low and beat in confectioners’ sugar, remaining 1/4 cup cereal milk, vanilla and salt until smooth. Increase speed to high; beat for 1 to 2 minutes or until frosting is light and fluffy.

Transfer frosting to piping bag fitted with medium star tip. Pipe frosting evenly over cupcakes. Garnish with 3/4 cup cereal and sprinkles, dividing evenly.