Cook the pasta according to the manufacturer's instructions. Make sure to reserve 1 cup of the pasta water for later. Meanwhile, heat olive oil in a pan over medium heat. Add shallots, a pinch of salt, and pepper; sauté for 3-5 minutes. Then, add garlic and cook for an additional minute, until fragrant.

Crumble the sausage into the pan and cook for 5-7 minutes. Break up the sausage with a spoon until it is browned and cooked through.

Pour in a cup of broth, scraping up any bits from the bottom of the pan. Add the kale (or spinach) and cook until wilted, which should take about 3-5 minutes.

Next, add the parmesan cheese, the cooked rigatoni, and a cup of the reserved pasta water to the sausage and kale mixture. Stir and cook the ingredients together for about 3-5 minutes to coat the pasta. Finally, garnish with additional parmesan cheese and a sprinkle of crushed red pepper before serving.