Heat olive oil in a large pot over medium heat. Add the shallots and cook until softened.
Add the chopped mushrooms and cook until their liquid is gone.
Add the peas and garlic, cook briefly, then remove the mixture from the pot and set aside.
Pour in the chicken stock, just enough to cover the pasta, and bring to a simmer. Add the ditilini and cook, stirring often, until the liquid is almost gone and the pasta is al dente.
Return the mushroom mixture to the pot with the sun-dried tomatoes. Stir in the cream and pecorino until creamy. Season with salt and pepper to taste and serve with more pecorino on top.