Put the tomatillos, 2 of the apples, the onion, garlic,and jalapeño chile on a rimmed baking sheet. Toss with theolive oil and season with salt and pepper. Roast untiltomatillos are softened and slightly charred, about20 minutes.
Peel the garlic, then transfer all of the ingredients to ablender and puree until smooth. Season with salt andpepper.
Chop the remaining apple into 1/4-inch cubes and stirinto the salsa before serving.