Fill a medium pot (or large for 4 servings) 3/4 of the way up with salted water; cover and heat to boiling on high. Wash and dry the fresh produce. Cut off and discard the bottom 1/2 inch of the broccoli stem; cut the broccoli into small florets. Halve, peel, and thinly slice the onion(s). Thinly slice the mushrooms. Grate the grand cru on the large side of a box grater.

Add the pasta to the pot of boiling water. Cook, stirring occasionally, 5 minutes. Add the broccoli florets. Cook, stirring occasionally, 2 to 4 minutes, until the broccoli is tender and the pasta is al dente (still slightly firm to the bite). Turn off the heat. Drain thoroughly and return to the pot.

In a medium nonstick pan (or large for 4 servings), heat a drizzle of olive oil on medium-high until hot. Add the sliced onion(s); season with salt and pepper. Cook, stirring occasionally, 3 to 4 minutes, or until lightly browned and slightly softened. Add the sliced mushrooms; season with salt and pepper. Cook, stirring occasionally, 5 to 6 minutes, or until browned. Turn off the heat.

To the pot of cooked pasta and broccoli, add the cooked vegetables, béchamel, and cream (shaking the packet before opening). Cook on medium-high, stirring constantly, 1 to 2 minutes, or until thoroughly coated and combined. Turn off the heat. Add the grated grand cru and stir until melted and combined. Taste, then season with salt and pepper if desired. Serve the finished pasta garnished with the parmesan. Enjoy!