Can I make popper onion cups ahead of time?
Yes, assemble them up to 4 hours ahead, cover, and refrigerate. Bake from cold, adding 5–10 minutes to the cooking time.
How do I keep the onion cups crispy?
Coat the onion rings evenly in the cornstarch and egg mixture, then bake at a consistent temperature. Don't cover them while baking, and serve immediately after cooking.
Can I use a different cheese instead of sharp cheddar?
Yes. Monterey Jack, pepper jack (for more heat), or a blend of cheddar and mozzarella all work well. Avoid very soft cheeses that won't hold their shape.
What's the best way to slice onions into cup shapes?
Cut white onions horizontally into 1/2-inch thick rings, then carefully separate the layers. The outer rings form natural cups; inner rings can be layered or reserved for another use.
Can I make these spicier?
Use a spicy sausage blend, add sliced serrano or habanero peppers instead of jalapeño, or include a pinch of cayenne in the sausage filling.