Deep-frying cooks food in hot oil and gives it a crispy outside.

Cookbook author Betty Liu uses this method in the "Frying" chapter of her book "The Chinese Way."

She aims for 350°F to 375°F and uses a thermometer.

A wooden chopstick can also test the heat.

Tiny bubbles rising fast mean the oil is ready.

Deep-frying often uses a double-fry technique, long used in Shanghai for shrimp and fish steaks.

Liu says it works especially well for chicken.

The first fry at a low temperature seals in juices and sets a light coating.

The second fry at a higher temperature cooks the chicken through and makes it crispier.

Her coating uses cumin for seasoning and crushed sesame seeds for texture.

The chicken marinates for at least 4 hours or overnight.

It is then coated in a mix of sesame seeds, sugar, potato starch and cumin.

The first fry happens at 335°F for about 90 seconds.

The second fry is at 350°F for 3 to 5 minutes, until the chicken reaches 165°F inside.

Liu serves the chicken with a cumin salt and an optional lemon mayonnaise.

She is a cookbook author, photographer and doctor finishing her surgical residency.

She writes about Chinese home cooking on her award-winning blog.

Her first book, "My Shanghai," came out in 2021 and was named one of the year's best cookbooks.