Combine onion, lemon juice, and sugar. Toss to combine while separating the onions. Let sit for 10 minutes.
Using a gloved hand, add potato starch, black pepper, paprika, and salt. If you let it sit too much at this point, you need to add 1 tablespoon of potato starch before frying.
Heat oil in a saucepan or deep fryer. Deep fry until golden brown. Stir once while frying so they don’t stick. Drain and cool.
To freezer, let cool completely. Place in a plastic container, cover and freeze. To thaw, spread out frozen on a baking sheet. Warm up uncovered in oven until heated throughout (time will depend on your oven temperature).
Notes
Frenched onions are onions sliced lengthwise with the grain, from root to stem, ideal for caramelizing or frying.