Deep-frying cooks food in hot oil.

It gives the food 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.

She uses a thermometer to check the heat.

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.

This method has long been used in Shanghai for shrimp and fish steaks.

Liu says it works especially well for chicken.

The first fry is at a low temperature.

It seals in juices and sets a light coating.

The second fry is at a higher temperature.

It cooks the chicken through and makes it crispier.

Her coating uses cumin for seasoning.

It also uses crushed sesame seeds for texture.

The chicken marinates for at least 4 hours or overnight.

Then it is 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.

It lasts until the chicken reaches 165°F inside.

Liu serves the chicken with a cumin salt.

She also offers an optional lemon mayonnaise.

She is a cookbook author, photographer and doctor.

She is finishing her surgical residency.

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

Her first book, "My Shanghai," came out in 2021.

It was named one of the year's best cookbooks.