You can't get any more fundamental than this preparation -- the sauce calls for only two ingredients, plus a sprinkle of salt and pepper to finish.
Heat butter in a large heavy-bottom skillet over medium-high heat until foam subsides and butter begins to brown. Add sage; cook, stirring, until leaves are crisp and butter is golden brown. Transfer sage leaves to a paper-towel-lined plate to drain. Reserve brown butter in skillet with heat off.
Lightly brush a rimmed baking sheet with oil; set aside. Bring a large pot of water to a boil; add the salt. Add half the gnocchi; when they rise to the top (after about 2 minutes), continue to cook until tender, about 15 seconds more. Transfer gnocchi with a slotted spoon to oiled baking sheet. Repeat process with remaining gnocchi.
Reheat reserved brown butter over medium heat. Add gnocchi; cook, stirring occasionally, until heated through. Season with salt and pepper. Add reserved sage leaves, and gently toss.