Heat the oil in a large saute pan over medium heat. Add the shallots and cook, stirring, until shallots are soft, about 2 minutes. Add the garlic and cook for 1 minute more. Add the escarole and cook, stirring, until it has wilted, about 5 minutes. Add the chicken broth, and chili flakes. Bring simmer and cook over a medium heat, stirring occasionally, another 3 minutes. Add the vinegar and cook for 2 minutes more. Season with salt and pepper. Stir in pine nuts just before serving.
Excellent source of: Vitamin A, Folate, Vitamin K, Manganese