Preheat the oven to 400 degrees F.

Prick the potatoes with a fork and place them in the oven directly on the rack on a sheet of aluminum foil. Bake 40-45 minutes until they are tender and can be pierced easily with a knife.

When the potatoes are cool enough to handle, halve them, scoop out the flesh and feed through a potato ricer or food mill into a large bowl. Whisk in the egg, Parmesan, salt and pepper. Fold in 1 cup flour and add the rest of the flour in small amounts until you have a workable dough that is barely sticky. You may not need all the flour.

On a lightly floured work surface take a handful of dough and roll it into a 1/2-inch thick rope. Cut the rope into 1-inch pieces and roll down the tines of the back of a fork. Transfer the gnocchi to a flour-dusted sheet pan.

In a large skillet, melt the butter over medium high heat. When the butter starts to turn brown and smells nutty, fry the sage leaves until crisp, about 20 seconds. Remove the sage from the butter and take the skillet off the heat when the butter is golden brown.

Bring a large pot of salted water to a boil. Cook a quarter of the gnocchi for about 3 minutes until they float to the top. Use a slotted spoon transfer to a bowl and cook the remaining gnocchi.

Return the brown butter to medium heat and gently toss the gnocchi in the butter until they are browned at the edges. Serve topped with sage and Parmesan.