Cut off and discard the tough ends of the broccoli rabe and cut the rest of into 2-inch pieces. Place the broccoli in a colander and rinse. Drain well. Heat the olive oil in a large pot. Add the garlic and cook over low heat, stirring occasionally, for 4 to 6 minutes, until golden brown. Remove the garlic with a slotted spoon, and set aside. Add the broccoli to the hot oil. Add the red pepper flakes, salt, and pepper and cook, covered, over medium to low heat for 5 to 10 minutes, turning occasionally with tongs, until the stalks are tender but still al dente. Add the reserved garlic, check the seasonings, and serve hot.