Wash the green asparagus thoroughly, trim the ends, and peel the lower quarter of any thick spears. Cut them into 1/3-inch diagonal slices, ensuring to leave the tips whole.

Bring a large pot of salted water to a boil and add the spaghetti. Cook according to package directions, usually around 8–10 minutes, until al dente.

In a large skillet, melt a generous tablespoon of salted butter over medium heat. Add asparagus pieces and sauté for about 5 minutes until crisp-tender and bright green.

In the pot used for the spaghetti, combine the drained pasta with crème fraîche, lemon zest, and black pepper. Heat over low while stirring until creamy.

Gradually add reserved pasta water, one tablespoon at a time, mixing well after each addition to achieve the desired sauce consistency.

Stir in freshly grated Parmesan cheese and adjust with more pasta water as needed, tasting and seasoning with salt and pepper.

Squeeze fresh lemon juice over sautéed asparagus and stir. Gently fold the creamy pasta sauce with most of the asparagus.

Plate the creamy asparagus pasta and garnish with reserved asparagus tips, extra lemon zest, additional grated Parmesan, and a sprinkle of black pepper.