In large saucepot, prepare pasta in boiling salted water as label directs.
Meanwhile, in 12-inch skillet, heat olive oil over medium heat until hot. Add garlic and cook 1 minute, stirring. Gradually add spinach and 2 tablespoons water; cook, stirring often, just until spinach wilts. Remove skillet from heat.
When pasta has cooked to desired doneness, remove 1 cup pasta cooking water. Drain pasta; return to saucepot. Add ricotta cheese, Parmesan cheese, pepper, 1/2 teaspoon salt, spinach mixture, and reserved cooking water; heat over medium heat, tossing until well blended. Garnish with shredded Parmesan cheese to serve.