Trim ends off asparagus and then cut the stalks into one-inch pieces.

Put the pieces into a food processor, and process until it is finely chopped.

Save out about one cup of the asparagus mixture and set it aside.

Heat a large skillet over medium heat, and melt the butter in it.

When the butter is melted, add the onion and 1/4 teaspoon salt, and saute until the onion is soft.

Add in the garlic and saute for about one minute. Add in the remaining asparagus from the food processor and stir to combine the ingredients. Let it saute for four to five minutes, stirring regularly.

While the asparagus sautes, begin cooking your pasta, according to the package instructions. When it’s done, be sure to reserve at least one cup of the pasta water when you drain it.

Once the asparagus is just starting to brown a bit, add in the heavy cream. Once it comes to a low simmer, add in the reserved asparagus, and stir.

Continue stirring regularly, letting the cream reduce a bit until dragging a spatula across the bottom of the pan leaves an empty trail for a few seconds before the sauce runs back into it.

Turn the heat to low and stir in the parmesan.

Add your drained pasta to the skillet. Add a touch of the pasta water, and toss the pasta with the sauce. If you want the sauce a little looser, add more pasta water until it’s at a consistency you like. Stir in the lemon juice and more salt and pepper, to taste. Serve with a little more fresh parmesan on top.