Mushroom Pappardelle with Gorgonzola Cream and Walnuts

Serves: 3

1lb./450 g. pappardelle
2 tbsp butter
24 sage leaves
1 lb./450 g mixed mushrooms (cinnamon cap, shitake, king oyster)
2 tbsp white wine
1 cup heavy cream
4 oz./113 g. Gorgonzola Dolce, plus more to taste
¼ cup chopped walnuts, toasted