Cook the spaghetti in a large pot of boiling salt water until al dente. Drain and set aside.
Snap the rough ends of the asparagus and discard. Cut the asparagus into 1-inch pieces.
Heat a large skillet with olive oil. Add minced onion and garlic, sauté for 3 minutes. Add asparagus and roast for 5 minutes. Season with a generous pinch of salt and pepper.
Mix all ingredients for the carbonara sauce in a bowl.
Add drained spaghetti and carbonara sauce to the skillet with the asparagus and toss for a few minutes over low heat until the sauce starts to thicken slightly. → You want to avoid that the carbonara sauce gets too hot or your eggs begin to scramble. Alternatively, take the skillet off the heat completely to prevent scrambled eggs, although I prefer when the sauce thickens just a tiny bit rather than being super runny! Up to you!
Season to taste with salt and black pepper. Feel free to top it with additional parmesan cheese and chopped parsley or chives.
Notes
Dairy-Free: This carbonara can be made dairy-free!
Vegan Option: If you prefer a vegan asparagus carbonara, use the vegan carbonara sauce from this Vegan Carbonara Recipe.
Keeps fresh for 3 days. Store it in an airtight container in the refrigerator. Although I highly recommend cooking only as much so that you don't end up with leftovers as freshly cooked carbonara tastes best. If you reheat it, the eggs get cooked, resulting in a dry carbonara sauce. Still delicious, but not as creamy. 😉