I keep a few small plastic flowers & pots clean just for this purpose. To keep ice cream from leaking out the drain holes, cut circles out of old plastic lids to place in bottom of pots.
Gather cookies to crush for your chocolate "potting soil dirt." No need to remove the white frosting. In fact it makes it look more like potting soil. It all crushes just fine.
I crush cookies with a rolling pin in a plastic bag. I don't even dirty a blender or food processor. Keep cookies COARSE... Do not crush to a fine powder.
I prefer vanilla but any ice cream that compliments Oreo cookies works.
Scoop ice cream into pots and press down tightly to compact, leaving 1/2-3/4" at the top to add your "dirt."
Tightly packed ice cream holds flower in place well. Spoon crushed cookies to cover ice cream. Keep in freezer till time to serve.
The fun part for you is watching people's reactions when you hand them one with a spoon, and tell them it's dessert! They taste delicious by the way!