1. Wash the sweet potato, cut it into small pieces, rinse it with cold water, wash off the surface starch, and drain the water.

Heat the oil pan to 7 minutes heat, add potato pieces and fry over low heat until cooked. Take it away.

2. Heat the oil to 90% heat and quickly fry it again until the surface turns yellow and brittle.

Take it away.

3. Heat the wok, add a little base oil, add pepper, fry until cooked, take out, and add tomato sauce, sugar and vinegar. A little water, stir well, pour in sweet potato pieces, stir fry quickly, and take out the pot quickly to prevent peeling on the surface of sweet potato pieces, which is not delicious.

Such sweet and sour potatoes with ketchup are successful.