Preheat oven to 425°F.

Line 2 baking sheets with parchment paper; set aside.

Wash and scrub potatoes. Using a fork, pierce each potato 8-10 times evenly around surface. Place potatoes on a microwave-safe plate and microwave on high for 4 minutes. Turn potatoes and microwave for 4 more minutes on high.

Transfer potatoes directly onto oven rack and bake for 20-22 minutes, or until a fork can easily pierce the potato.

Using a kitchen towel to hold the potatoes, peel each potato. Process peeled potatoes through a food mill. Place potatoes on a plate and let cool for 10 minutes.

Place 3 cups of potatoes in a large bowl. (Note: Remaining potatoes will not be used in this recipe. Save them for another use.)

Whisk egg together and add to the bowl with potatoes. Stir until just combined.

Add flour, salt and Parmesan cheese to the bowl. Stir until just combined.

Transfer mixture to a lightly-floured countertop. Knead mixture until smooth, adding additional flour to the countertop as necessary.

Divide dough into 8 equal pieces.

On a lightly-floured countertop, roll/shape each piece into a rope approximately ½” thick.

Cut rope into segments about ¾” in length. Using the back of a fork, gently press down on each segment to create ridges in the dough.

Transfer gnocchi onto the lined baking sheets. (Note: Ensure that gnocchi are not touching one another on the sheet.)

Bring a large pot of water to a boil over high heat. Once boiling, add approximately 1/3 of the gnocchi to the pot. Cook for 1½-2 minutes. Remove gnocchi from water with a slotted spoon and transfer into a large skillet. (Note: The gnocchi will rise to the surface after about 1-1½ minutes. Cook for 30 seconds more once they rise to the surface.)

Repeat with remaining gnocchi.

Place a medium skillet over medium-low heat. Add butter and stir gently until butter has fully melted. (Note: This should be a different skillet than the one holding the cooked gnocchi.)

Add the minced garlic and sage. Cook, stirring constantly, until butter develops a nutty smell and dark flecks begin to appear (~5-6 minutes).

Transfer Sage Brown Butter Sauce into skillet with cooked gnocchi. Heat over medium heat, stirring occasionally, for 1-2 minutes.

Garnish with additional shaved Parmesan before serving. (optional)