Fresh tortellini, plus a quick pesto make for a surprisingly quick and lovely meal.
In a food processor, combine Parmesan and half the arugula; pulse until coarsely chopped. With motor running, add oil in a thin stream, and process into a rough paste; season pesto with salt and pepper. Set aside.
In a large saucepan, bring broth and 3 cups water to a boil. Add tortellini, and cook until al dente, according to package instructions. Remove from heat; stir in remaining arugula and lemon juice, and season with salt and pepper. Ladle tortellini and broth into bowls, and serve with pesto-topped toasts.