1. Combine lentils and 4 cups water in a saucepan; simmer, uncovered, 20 minutes or until just tender. Drain.
2. Meanwhile, cut out and discard escarole stems; separate leaves. Rinse. Chop coarsely.
3. Heat oil in a 4-quart pot over medium-high heat. Add sausage; cook, breaking up any clumps with a wooden spoon, for about 3 minutes or until no longer pink. Add onion and escarole; cook 3 minutes, stirring occasionally. Add remaining 4 cups water and broth granules. Bring to a boil; lower heat; simmer, covered, 15 minutes.
4. Add lentils and pepper flakes; simmer 3 minutes more.
5. Ladle into 4 bowls. Top each with cheese, dividing equally. Makes 4 servings.