In a medium saucepan, set over medium heat, add the butter. When melted, add the shallot and garlic. Cook until the shallot has softened, about 2 to 3 minutes. Mix in the chile powder, cumin, salt, oregano, coriander, cayenne and cloves. Cook for 1 to 2 minutes, until the spices are fragrant. Add the pumpkin puree, yogurt or crème fraîche and mix until warmed, about 2 to 3 minutes. Give it a taste and adjust the salt to your liking. It might be a bit salty but it’s ok because the pasta will need it! Set aside.