Bring a large pot of salted water to a boil and cook the pasta al dente according to package directions.
Meanwhile, in a skillet, melt the butter and olive oil over medium heat.
Cut the asparagus into roughly 1.5" pieces. Add the asparagus to the pan and cook for 3-5 minutes (depending on thickness of asparagus).
Add the mushrooms to the skillet and cook for a few minutes, until the mushrooms are softened.
Add the garlic, lemon juice, and salt and pepper. Stir and cook for a couple more minutes. Prior to draining the pasta, you can add a few tablespoons of the hot pasta water to the skillet if desired. Add the drained pasta to the skillet and toss until combined. Serve immediately with freshly grated parmesan cheese.
