Preheat oven to 350°F. Butter three 8-in. round cake pans; line pan bottoms with parchment paper. Set aside. Whisk together flour, cornstarch, baking powder, and salt in a medium bowl; set aside.
Beat sugar and butter in a stand mixer fitted with a paddle attachment on medium speed until fluffy, 3 to 4 minutes. Add egg whites 1 at a time, beating well after each addition. Reduce mixer speed to low, and beat in oil, vanilla, and almond extract to incorporate, 1 to 2 minutes.
With mixer running on low speed, add flour mixture to sugar mixture in 3 additions, alternating with 2 additions of milk, and beating until just combined after each addition. Gently fold in sprinkles using a rubber spatula and evenly distributing. Divide batter evenly among prepared cake pans.
Bake until a wooden pick inserted into centers of the layers comes out clean, 22 to 25 minutes. Let cool 10 minutes. Remove the layers from pans, and transfer to a wire rack. Let cool completely, about 1 hour.
Beat butter in a stand mixer fitted with a paddle attachment on medium speed until smooth, about 1 minute. Reduce mixer speed to low; gradually add confectioners' sugar and beat until combined and smooth, 2 to 3 minutes. Increase mixer speed to medium; beat in milk, vanilla, almond extract, and salt until combined, 2 to 3 minutes.
Place 1 cake layer on a platter; spread top evenly with some of the frosting. Top with second cake layer; spread top evenly with some of the frosting. Top with remaining cake layer; spread top and sides of cake with remaining frosting.
Cut 10 strips of paper in various colors about 1/4 in. wide and 1 in. long. Make a loop using 1 strip and secure with glue. Insert a paper strip in a different color into the loop and glue it to make an interconnected loop. Repeat 8 times. Adhere each end to a wooden skewer.