Combine crumbled sausage, shallot and garlic in a large saucepan over medium heat. Cook, stirring, until the sausage is cooked through and starting to brown, 4 to 5 minutes. Increase heat to high and stir in broth, sour cream, pepper and salt. Add orecchiette, bring to a boil and cook, stirring frequently, until the pasta is just tender and the liquid has mostly evaporated, about 12 minutes. Remove from heat and stir in peas and Parmesan. Let stand for at least 5 minutes, stirring occasionally, before serving.