Preparation Working over a small bowl, finely grate enough zest from lemon to measure 2 teaspoons. Cut lemon in half; squeeze juice into another small bowl. Set zest and juice aside. Heat oil in a large skillet over medium heat. Add garlic and cook, stirring often, until garlic is beginning to turn golden at edges, about 2 minutes. Add ham; cook, spreading out ham with tongs to keep pieces from sticking together, until crisp, about 2 minutes. Add red pepper flakes; stir for 30 seconds, then add escarole. Cook, tossing escarole to coat in sauce, until wilted but not overcooked, 3-5 minutes. Season with salt and pepper. Using tongs, transfer escarole to a serving dish. Add butter, lemon zest, and lemon juice to taste to pan. Cook, whisking, until a sauce forms. Season with salt and pepper. Drizzle sauce over escarole.
Preparation Working over a small bowl, finely grate enough zest from lemon to measure 2 teaspoons. Cut lemon in half; squeeze juice into another small bowl. Set zest and juice aside. Heat oil in a large skillet over medium heat. Add garlic and cook, stirring often, until garlic is beginning to turn golden at edges, about 2 minutes. Add ham; cook, spreading out ham with tongs to keep pieces from sticking together, until crisp, about 2 minutes. Add red pepper flakes; stir for 30 seconds, then add escarole. Cook, tossing escarole to coat in sauce, until wilted but not overcooked, 3-5 minutes. Season with salt and pepper. Using tongs, transfer escarole to a serving dish. Add butter, lemon zest, and lemon juice to taste to pan. Cook, whisking, until a sauce forms. Season with salt and pepper. Drizzle sauce over escarole.