Cut lengthwise around the middle of the avocados, then twist to separate the halves. Remove the pits by striking them with a knife blade, then scoop out the flesh with a spoon and dice.
Combine the avocados, tomatillos, onion, cilantro, jalapeno, lime juice, 1/2 teaspoon salt and 1/4 teaspoon pepper in a medium bowl and gently mix.
Raw tomatillos give this salsa a great tart, acidic flavor.
Recipe courtesy of Aaron Sanchez for Food Network Magazine