Place bacon in a large skillet over medium-high heat. Cook until crisp, 7 to 8 minutes. Remove the bacon and reserve the drippings in the pan. Add olive oil to the drippings and heat for 1 minute. Add the escarole; cook and stir for 3 to 4 minutes. Stir in the garlic, and continue cooking and stirring until fragrant, about 1 minute. Pour in the chicken broth and beans, and season with red pepper flakes. Simmer for 5 to 7 minutes. Ladle into bowls to serve and top with the crumbled bacon and Parmesan cheese.