KUNG PAO CHICKEN
KUNG PAO CHICKEN IS A RESTAURANT FAVORITE. Bits of silky chicken swim in a spicy, dark brown sauce along with peanuts and dried red chiles. Kung pao is not only spicy, it is rich. It typically contains few vegetables or none, making it uncharacteristic of most Chinese dishes. It should be served with plenty of rice to cut the heat and at least one vegetable dish to round out the meal. The biggest challenges when preparing kung pao are getting the texture of the chicken right and infusing the dish with enough—but not too much—heat.
The texture of the chicken in this dish is different from that in a stir-fry. The exterior is an unusual combination of silky and crisp. In most restaurant kitchens, cooks obtain this crispiness by deep-frying (submerging the chicken in hot oil) and then draining the chicken. Chiles and aromatics are then stir-fried (cooked in a thin film of oil), and the sauce and chicken are added back at the end. We tested deep-frying as well as pan-frying (cooking the chicken in a shallow depth of oil) and got great results with pan-frying the chicken in just three tablespoons of oil. The oil is drained off after the chicken is cooked.
Pan-frying (or deep-frying in restaurants) is what gives the chicken its crisp crust, but the desired silkiness comes from the marinade. Some sources suggest "velveting" the chicken in egg white; others add some cornstarch and/or oil to the marinade.
We tested velveting first, adding egg whites and cornstarch to a simple rice wine and soy sauce marinade. We prepared a second batch with cornstarch alone added to the rice wine and soy sauce. For the third batch, we included neither cornstarch nor egg white.
Tasters agreed that adding cornstarch to the marinade was a good idea. It gave the chicken the silky, tender texture we wanted. Egg white and cornstarch performed on a par with the cornstarch-only mixture, so we opted to omit the egg white. We had also seen recipes that called for a little oil. We tried this tip and found that oil helps to keep the chicken pieces separate when cooked, which in turn improves the texture of the meat.
Until this point in the testing, we had been cooking diced chicken breasts with good results. We wondered how chicken thighs would do. Tasters felt that the thighs were even better—meatier, juicier, and more flavorful.
Chicken is traditionally diced for kung pao; tasters preferred a small 1/2-inch dice. We found that one pound of diced chicken could be comfortably cooked in a 12-inch skillet. Add any more chicken and it has to be cooked in batches to ensure that it will brown well and not stew in its own juices. Given the waste associated with chicken thighs (they contain a fair amount of fat that should be trimmed), we decided to buy 11/4 pounds of chicken to yield the pound needed for the recipe.
With the chicken element under control, we turned our attention to the heat level. Traditionally, kung pao chicken comes to the table filled with toasted dried red chiles. To release the flavor and heat from the chiles, we found it is necessary to break them in half before toasting them in the oil. Most of the heat in a chile pepper is found in the seeds and interior ribbing, not the outer shell.
Because dried red chiles are sometimes not easy to come by, we wondered if hot red pepper flakes could be used instead. While toasting dried chiles in oil releases their flavor, pepper flakes tasted burned when cooked this way. We found it better to add them with the aromatics (garlic, ginger, and scallions) toward the end of the cooking time.
Tasters felt that kung pao chicken made with hot red pepper flakes instead of dried chiles looked a bit odd. We found that adding some diced red bell pepper helped solved this problem. The charred bits of bell pepper add some visual contrast that the chicken needs. Their sweetness is also a good foil for the rich, spicy flavors in this dish.
In the end, tasters preferred the heat given by the dried red chiles. They seemed to have a fuller flavor than the pepper flakes, which were merely spicy. Because of the way the dried chiles are cooked, the flavor permeates the dish and blends with its sweet, sour, and salty elements. Hot red pepper flakes stand out. You taste heat, then the sweet, sour, and salty flavors. It's not that the hot red pepper flakes are bad; they just aren't as good.
Our next challenge was to assemble the elements of the sauce. Kung pao has a complex, brown sauce with strong sweet and sour notes to balance the heat of the chiles. Chicken broth, soy sauce, rice wine, and vinegar were pretty much standard in the recipes we consulted. We found that too much vinegar made the sauce harsh. A good deal of sweetness was also essential. In recipes that called for little or no sugar, the heat was one-dimensional. We found that a full tablespoon of sugar is best.
Because cornstarch generally makes stir-fry sauces too thick, we tend to shy away from it. However, the ingredients in kung pao—diced chicken, diced red bell pepper, and peanuts—are so smooth that the sauce was not adhering properly. We tried reducing the sauce before adding the cooked chicken back to the pan. This helped, but the sauce was still pooling. We found that just 1/2 teaspoon of corn starch solved this problem. Any more cornstarch—even just an extra 1/2 teaspoon—turns the sauce gummy, so measure carefully.
The aromatic elements (garlic, ginger, and scallions) were fairly easy to incorporate. Tasters liked more scallions in this dish for contrast with the chicken and peanut flavors. Cutting scallions into 1/2-inch lengths rather than mincing made them seem more like a vegetable and helped to maintain freshness, a quality otherwise missing from this dish.
We tried other vegetables—mushrooms, water chestnuts, and celery—but tasters consistently preferred a streamlined dish of just chicken, diced red bell pepper, and peanuts. One final note: Use a nonstick skillet. If you don't, plan on adding more oil to keep the chicken from sticking.