Season the chicken pieces with salt and black pepper to taste.
1 pound boneless, skinless chicken breasts, salt and black pepper
Add the cornstarch to a shallow bowl. Dredge each chicken piece in the cornstarch, shaking off any excess.
½ cup cornstarch
Heat vegetable oil in a large skillet or frying pan over medium-high heat. Add enough oil to fully coat the bottom of the pan. It should be about ¼ inch deep from the bottom of the pan. Once the oil is hot, carefully add the coated chicken pieces about 1 inch apart. Do not add too many chicken pieces at once. Fry them until they are golden brown and fully cooked, typically taking about 1 to 1.5 minutes per side. Be careful not to overcook the chicken. Remove them from the skillet and drain on paper towels. Repeat with any remaining chicken pieces. Note 4.
vegetable oil
In a small bowl, add the orange marmalade, soy sauce, and rice vinegar. Whisk until it's well combined. Heat it in the microwave on high for 40 seconds to 1 minute until it is heated through. If the sauce is too thin, mix some cornstarch with water and stir it in until thickened or you can add a bit more marmalade. Note 5.
¾ cup orange marmalade, 2 tablespoons soy sauce, 1 tablespoon rice vinegar
Pour it over the chicken and toss to coat. Serve it over cooked rice or noodles.