Bring a large pot of salted water to a boil.
Cook the gnocchi according to package directions until they float to the surface.
Reserve 1/4 cup of pasta water and drain the gnocchi.
Meanwhile, melt the butter in a large skillet over medium heat.
Cook the butter for 3 to 5 minutes, stirring often, until golden brown and fragrant.
Add the walnuts and sage leaves.
Cook for 1 to 2 minutes until the walnuts are toasted and the sage becomes crisp.
Add the cooked gnocchi to the skillet.
Gently toss to coat the gnocchi in the brown butter mixture.
Add a splash of reserved pasta water if needed.
Season with salt and pepper.
Stir in the Parmesan cheese.
Serve immediately with extra Parmesan on top.