Mozzarella sticks have no depth perception -- deep-fry them in several inches of oil or pan-fry them in a half-inch of oil, and they cook to golden brown either way -- but you have to use a slightly different frying technique when using the lesser amount of oil.
Choosing the Pan
Pan-frying requires a heavy straight-sided pan -- cast-iron or stainless-steel skillets work best. Unlike the saute technique, which requires quick flicks of the wrist to turn the food over rapidly, pan-frying requires little to no pan movement -- the longer the pan stays on the burner the more stable the oil temperature. This makes heavy-bottomed pans the safest and most effective choice for the cooking method.
Add 1/3 to 1/2 inch of vegetable oil to the skillet. Set the heat of the stove to medium and let the oil heat for 3 to 4 minutes. Medium heat falls between 325 to 374 F, the optimum temperature range for frying frozen food.
Lay the frozen mozzarella sticks in the oil using a slotted spoon or tongs without overcrowding the pan; leave at least 1 inch of space around each piece. Disturb the oil as little as possible to prevent splattering.
Move the mozzarella sticks in the oil using tongs so they don't stick to each other; monitor and move them for 15 to 20 seconds, which is long enough to prevent sticking. Fry the sticks for 1 1/2 minutes without moving them.
Turn the mozzarella sticks over using tongs. Some piece might roll over on their own in the oil, some may not. Turn the sticks over so each side gets about 1 1/2 minutes of full oil contact, or about 3 minutes of total cooking time.
Transfer the mozzarella sticks to the wire rack when they turn golden brown and cheese starts to ooze from the crust in some spots. Using a wire rack to drain the sticks instead of paper towels produces a crisper crust. Wire racks let the crust "breathe," whereas paper towels smother it, producing steam as a result; steamy crust equals soggy crust.