1. Combine apple, vinegar, hot sauce, scallion, parsley, salt, and pepper in blender; pulse, scraping down blender jar and adding water as needed, until very finely chopped. With machine running, gradually add oil, scraping down blender jar as needed. (Can be refrigerated up to 1 week.)

2. To serve four, toss greens with 4 tablespoons dressing; serve imediately.

Dressing makes 1 1/2 cups