Pour
enough vegetable oil in a large pot to come up two inches and heat to 375 degrees F on a deep - fry thermometer.
Pour
enough vegetable oil into a heavy - bottomed skillet so that it is about 1 / 4 - inch deep, and heat over medium heat to about 350 degrees.
If oven - frying: Preheat oven to 375 °F have ready two shallow, rimmed baking sheets
with enough vegetable oil to generously coat the bottoms.
Toss the sweet potato wedges in
just enough vegetable oil to coat them, then lay them out on a baking tray and roast at 200 °C / 400 °F / gas mark 6 until golden and crunchy.
(or cook them in two batches) Pour in
enough vegetable oil to come 1/4 inch up the sides.
When the wok is hot, add just
enough vegetable oil to lightly coat the pan, 1 - 2 teaspoons, and swirl it until evenly coated.
Wipe out the soup pot and heat just
enough vegetable oil to coat the bottom.