Bring large pot of salted water to boiling. Combine vodka, cream and pepper flakes in large skillet.
Bring to boiling. Reduce heat; simmer 5 minutes or until the mixture is reduced to about half. Stir in the marinara sauce; bring to a bare simmer.
Meanwhile, cook tortellini in boiling water for 12 minutes or until firm but tender. Drain well; toss with sauce and half of cheese. Place on serving dish. Top with remaining Parmesan. Makes 6 servings.