How to Make It
Heat the oven to 325°. In a large pot of boiling, salted water, cook the broccoli rabe until almost tender, about 3 minutes. Drain. Rinse the broccoli rabe with cold water and drain thoroughly. Cut the broccoli rabe into 2-inch lengths and set aside.
In a large bowl, beat the eggs with the ricotta and 1/4 teaspoon each of the salt and the pepper.
In a medium cast-iron or ovenproof nonstick frying pan, heat the oil over moderate heat. Add the garlic and cook, stirring, until fragrant, about 30 seconds. Add the blanched broccoli rabe and the remaining 1/2 teaspoon salt and 1/4teaspoon pepper and cook, stirring, for 2 minutes.
Evenly distribute the broccoli rabe in the pan and then add the egg mixture. Cook the frittata, without stirring, until the edges start to set, about 2 minutes. Sprinkle the Parmesan over the top and bake until firm, about 25 minutes.
Broccoli rabe is, frankly, bitter—usually appealingly so, but sometimes the bitterness can be overwhelming. Blanching the vegetable in boiling salted water for a few minutes before proceeding with the recipe tempers its strength. The trick, used here, can be applied to almost any dish.