Set out the ice cream to soften for about 15 minutes.
When it is soft enough to stir, pour all of the ice cream into the bowl of a stand mixer fitted with the paddle attachment. Turn the mixer to medium-high and beat the ice cream until smooth. You can also stir with a spatula or wooden spoon, but allow the ice cream to soften a bit more if you'll be stirring by hand.
Add the cake crumbs and continue beating on medium-high speed until all of the cake crumbs are incorporated.
Turn off the mixer then stir in the sprinkles with a large spatula until evenly dispersed.
Dollop the frosting into the bowl, then stir a few times to blend the frosting into the ice cream while keeping it in small chunks to create frosting swirls.
Transfer the ice cream to a freezer-safe container (like a metal loaf pan), top with additional cake crumbs and sprinkles, if desired, and allow to freeze for at least 2 hours.
Ice cream base: feel free to make your own ice cream base! Combine 2 cups (480mL) heavy cream, 1 cup (240mL) whole milk, ¾ cup (150g) granulated sugar, 2 teaspoons vanilla extract, and ⅛ teaspoon salt in a large bowl, then pour into a moving, frozen ice cream maker with the dasher in place. Churn for 20-30 minutes then proceed with step 3.
Cake and frosting: these are suggested amounts. I do not recommend using more than these amounts. You can also use 2-3 homemade cupcakes with frosting.