Remove the wax from the Babybel cheese minis. Cut the onions into wide, thick rings, and separate them. Ensure the rings are wide enough to hold a single cheese wheel. At least two rings per onion should be adequate.
Spoon the pesto into the mashed potatoes and mix well. Transfer one tbsp. of pesto mashed potatoes to each red onion ring. Press one mini cheese wheel into each potato-filled onion ring. Add another spoonful of potatoes on top of the cheese so that the onion ring is filled to the rim. Smooth the top layer of potatoes with the back of the spoon, and freeze for 30 minutes.
Bread the rings by dipping each one in flour, then egg, and finally breadcrumbs. For extra crispy poppers, dip the rings a second time in the egg and breadcrumbs.
Fry the rings in a pot of vegetable oil until golden brown.
