Cook pasta in a large stockpot of generously-salted boiling water according to package instructions.  Drain, once it reaches al dente.

While the pasta water is coming to a boil, melt butter in a large saute pan over medium-high heat.  Stir in mushrooms mushrooms and season with a pinch of salt and pepper.  Saute for 4-5 minutes until they are browned around the edges and cooked through, stirring occasionally.  Transfer mushrooms to a separate plate, and return saute pan to the heat.

Add olive oil to the pan and heat for 30 seconds, or until shimmering.  Add the onion and saute for 3-4 minutes, or until mostly soft, stirring occasionally.  Stir in tomatoes and garlic and a few generous pinches of salt and pepper, and saute for an additional 2-3 minutes, stirring occasionally.  Add in wine, and stir to combine, being sure to scrape up any browned bits on the bottom of the pan.  Add in the spinach one handful at a time, stirring it in and waiting 1 minute or so until it is slightly wilted before adding the next batch.

Once the spinach is wilted and the pasta is cooked and drained, pour the vegetable mixture in with the pasta and stir to combine.  Serve warm, garnished with optional toppings if desired.