Bring a pot of salted water to a boil. Cook pasta according to package directions. (I like to cook it a minute over the al dente recommendation.)
Meanwhile heat olive oil in a large skillet set over medium heat. Add the shallots and cook until fragrant and tender, a few minutes. Mix in tomato paste and paprika. Cook on low heat for 30-60 seconds to develop the flavor.
Stir in pumpkin puree, vegetable stock, salt and nutmeg. Let simmer on medium heat until the sauce reduces a bit, about 5 minutes.
Whisk in butter, whipping cream and about half of the parmesan cheese. Keep cooking until all the ingredients melt into a creamy sauce. Taste and add more salt if needed, then remove from heat.
Once the pasta is cooked, reserve about 1 cup (240 ml) of water and drain the rest. Fold pasta into the sauce. Mix in as much pasta water as needed to get a creamy sauce. (I prefer a thicker sauce, so I only add about 1/2 cup.)
Serve orecchiette with leftover grated parmesan, chopped walnuts and parsley.