Peel the sweet potatoes and shred them on the large holes of a box grater or with a food processor shredding disc. Aim for long shreds rather than short ones.

Pile the shreds into a clean kitchen towel, gather the corners and twist hard over the sink. Keep squeezing past the point you think you are done. You should remove ⅓ to ½ cup of liquid.

Microwave the squeezed shreds in a covered bowl for 3 minutes, or steam them 4 minutes, then spread them on a plate and cool them completely. This makes the surface starch tacky so the shreds grip each other. Cooling matters, since warm shreds scramble the egg.

Combine the cooled shreds with the beaten egg, flour, cornstarch, salt, onion powder, smoked paprika and black pepper. Mix by hand until every shred is coated and a squeezed handful holds together.

Divide into 8 equal portions of about ⅓ cup each and press each into a disc 3 ½ inches across and ½ inch thick, compacting the edges inward with your palms. A ring mould or jar lid makes them uniform.

Chill the shaped patties on a lined tray for 20 minutes. Cold patties are firm patties and they flip cleanly.

Heat the oil in a large skillet over medium heat until it shimmers. Cook 4 patties at a time for 4 to 5 minutes per side, until deep orange brown and crisp. Flip once and only once.

Air fryer method: brush both faces with oil and cook at 380F for 12 to 14 minutes, flipping halfway, without crowding the basket. Oven method: 425F on a preheated oiled sheet pan, 12 minutes, flip, then 10 minutes more.

To freeze, flash freeze the raw shaped patties flat on a lined tray for 2 hours, then stack them with parchment between each one for up to 3 months. Cook straight from frozen with 4 to 6 minutes added, and never thaw them first.