Preheat your oven to the temperature specified on the cake mix box. Grease your mini bundt cake molds or silicone donut pans with cooking spray for easy removal.
Follow the instructions on the cake mix box to prepare the batter. Pour the batter evenly into your prepared mini bundt cake molds or donut pans. Fill them up to about 3/4 full, leaving some space for the ice cream later.
Bake according to the package directions for cupcakes or mini cakes. This will typically take around 15-20 minutes. A toothpick inserted into the center should come out clean when the cakes are done.
Add a thin layer of Oreo crunch on top of the freshly baked cakes and press down firmly to make a smooth layer.
Cover the cakes with plastic wrap, and place them the freezer for a few hours to make sure this half of the cake is frozen. This will prevent the ice cream from melting.
Fill the molds with ice cream over the frozen Oreo layer, leaving some space on top for the frosting. Smooth out the layer evenly with the back of a spoon.
Cover the cakes again with plastic wrap and freeze about 45 minutes, or until the ice cream is firm.
Optional: If using gel food coloring, add a few drops to the whipped cream frosting or Cool Whip to achieve your desired color.
Frost the tops of the mini donut ice cream cakes with the whipped cream frosting or Cool Whip. You can use a spoon or a piping bag for a more decorative touch.
Optional: Garnish with sprinkles.