Bring a large pot of salted water to a boil, then add whole wheat pasta. Cook according to the package instructions until al dente, usually around 8-10 minutes. Before draining, reserve about ½ cup of the cooking water to adjust the sauce consistency later. Drain the pasta and set aside.

In a medium saucepan, heat 2 tablespoons of olive oil over medium heat. Once the oil shimmers, add finely chopped garlic and sauté for 2-3 minutes, stirring frequently, until fragrant but not browned.

Stir in the canned pumpkin purée along with 1 cup of milk, 1 tablespoon of white wine vinegar, and 1 cup of vegetable stock. Whisk everything together until smooth, and let it simmer for about 5 minutes.

Incorporate 1 tablespoon of chopped fresh sage and ½ cup of grated Parmesan cheese into the sauce, and let it simmer for another 2-3 minutes.

Remove the saucepan from heat and fold in a couple of handfuls of baby spinach. Stir gently until the spinach wilts.

Add the drained pasta to the saucepan, tossing everything together until the pasta is well-coated with the creamy sauce. Use the reserved pasta water if needed.

Distribute the creamy sage pumpkin pasta into serving bowls. Garnish with chopped walnuts, toasted pumpkin seeds, and extra Parmesan cheese as desired.