In a medium bowl, whisk together the ricotta, whole egg, egg white, parmesan, salt, pepper, and nutmeg until the mixture is smooth and well combined.
Gently fold in the all-purpose flour using a spatula until a soft, slightly tacky dough forms, being careful not to overwork it.
Bring a large pot of water to a gentle simmer and season with a pinch of salt.
Using two small spoons, carefully drop oblong mounds of the ricotta mixture into the simmering water.
Cook the gnocchi for 3 to 4 minutes; they are ready once they float to the surface.
While the gnocchi cook, melt the ghee in a large non-stick skillet over medium heat and add the fresh sage leaves until they become crisp and fragrant.
Use a slotted spoon to transfer the floating gnocchi directly from the water into the skillet.
Add the fresh spinach to the skillet and toss everything gently for 1 minute until the spinach is wilted and the gnocchi are lightly golden and coated in the sage butter.