Risotto With Sausage and Parsley

sweet or hot Italian sausage

extra-virgin olive oil

kosher salt

Freshly ground black pepper

to 6 cups chicken stock, ideally homemade

to 2 tablespoons unsalted butter

large onion, peeled and diced

Arborio rice

dry white wine

packed and roughly grated Parmesan, plus more for serving

of 1 lemon

finely chopped Italian parsley leaves