Heat the olive oil in a large saute pan and, when hot, add the garlic and crushed red pepper and cook, stirring, until garlic is fragrant; do not allow the garlic to brown. Add the escarole, chicken broth, and salt and cover the pan. Cook until wilted, about 2 minutes. Uncover pan and continue to cook, stirring, until cooking juices are nearly evaporated and escarole is tender, 2 to 4 minutes. Taste and reseason, if necessary. Serve drizzled with lemon juice, to taste, and extra-virgin olive oil if desired.