Preheat the oven to 375°F (190°C).

Cook the gnocchi according to package instructions; drain and set aside.

Melt the butter in a large pan over medium heat. Add the minced garlic and sage, sautéing until fragrant, about 1-2 minutes.

Combine the pumpkin, ricotta, heavy cream, water, salt, pepper, and nutmeg into the pan; mix until well blended.

Add the cooked gnocchi to the sauce mixture and stir gently until the gnocchi is fully coated.

Transfer the mixture into a baking dish and top with mozzarella cheese.

Bake in the preheated oven for 20-25 minutes, or until the cheese is melted and bubbly, with a hint of golden color.