Prepare the ingredients: Peel the white asparagus and slice them into thin strips using a vegetable peeler. Finely chop the onion (or shallot) and garlic.

Cook the tagliatelle in a large pot of boiling salted water until al dente.

Meanwhile, heat the olive oil in a large skillet with the thyme sprig. Add the chopped onion and garlic, and sauté for 1 minute until fragrant.

Drain the al dente tagliatelle, then add them to the skillet. Gently toss to coat the pasta with the vegetables. Add salt to taste.

Serve hot, topped with a pinch of freshly ground black pepper to enhance the flavors.