Bring water to a boil, add a pinch of salt and add pasta, cook following package instructions (mine was 7 minutes). Add asparagus for the last 3 minutes of the pasta cooking and let them finish cooking together. Reserve 1 cup of the pasta water before draining (dipping in a coffee mug works great!).
Meanwhile, in the time it takes to cook the pasta, make the sauce. Heat a large skillet over medium low heat and melt butter. When butter starts to bubble and slightly brown (but not burn) add almonds and garlic and toss.
Season with salt and pepper and continue to stir butter mixture so it does not burn. Add rosemary
Drain pasta and asparagus and add to the butter mixture. Add in the reserved pasta water a 1/4 cup at a time to the sauce if needed. Mix well, adding grated Parmesan as you go.
Served topped with extra Parmesan, and continue adding the reserved pasta water if the pasta gets dry.