Egg whites give these quick, cheesy nibbles their exceptionally light texture. Bite-size portions make them the perfect mouth-popping accompaniment to an aperitif.
Heat 2 inches oil in a deep 3-quart heavy saucepan over moderate heat until it registers 360°F on thermometer.
While oil heats, mix together cheese, flour, pepper, and salt in a bowl until combined well. Beat whites in another bowl with an electric mixer until they just hold stiff peaks. Fold in 1/2 cup cheese mixture to lighten, then fold in remaining cheese mixture gently but thoroughly.
Drop about 8 teaspoons of batter, 1 teaspoon at a time, into oil and fry, turning occasionally, until balls of batter are puffed, crisp, and golden, about 2 minutes. Transfer with a slotted spoon to paper towels to drain briefly. Make 3 more batches in same manner, returning oil to 360°F between batches. Serve immediately.
