Bring a large pot of lightly salted water to a boil; add dandelion greens and cook until softened, about 1 minute. Transfer to a bowl with a slotted spoon, leaving water in the pot.
Return dandelion cooking water to a boil; add orecchiette and cook, stirring occasionally, until tender yet firm to the bite, about 11 minutes. Drain, reserving 1/2 cup pasta water.
Process 3/4 of the dandelion greens in a food processor until finely chopped. Add Parmesan cheese, pine nuts, mascarpone cheese, and olive oil; process until pesto is smooth. Season pesto with salt and black pepper.
Heat a large skillet over medium-high heat. Cook and stir sausage in the hot skillet until browned and crumbly, 5 to 7 minutes. Stir orecchiette, dandelion pesto, reserved pasta water, and remaining dandelion greens into sausage; bring to a simmer, reduce heat to low, and cook until slightly reduced, about 5 minutes. Ladle into bowls and garnish with Parmesan cheese.
