Pumpkin Gnocchi with Walnut Sauce

1 cup pumpkin puree (canned)
2 tbsp melted butter, cooled
1-1/2 cups all-purpose flour
1 egg yolk
1/2 tsp each: salt and pepper
1/4 tsp nutmeg
1/4 cup butter
1 cup Avanti walnuts, roughly chopped
2 tbsp chopped fresh sage
1/4 tsp each: salt and pepper
1/2 cup shaved Parmesan cheese

In large bowl, combine pumpkin and butter; add flour, yolk, salt, pepper and nutmeg. Knead into soft dough (if necessary, add more flour 1 tbsp at a time); divide into 4 sections. On floured surface, roll dough to 3/4-inch [2-cm] thickness; cut into 3/4-inch pieces, rolling each piece against the tines of a fork to create ridges. Repeat with remaining dough. In large pot, bring 6 cups salted water to boil. Cook gnocchi in 2 batches; dropping into water and cooking 2 minutes or until pieces float. Remove with slotted spoon to warmed bowl. Meanwhile, in skillet, melt butter over medium heat, cooking until it just starts to deepen in color. Add walnuts, sage, salt and pepper; cook 1 minute more. Drizzle walnut butter over gnocchi and top with shaved Parmesan.