A mixture of earthy and complimentary flavours
In a frying pan, melt the first amount of butter. Add the onions, garlic, and mushrooms. Saute for 10 minutes, or until the mushrooms are browned. Remove everything from pan, and place on the side for later.
Cook the pasta until it's al dente while the mushroom are cooking. In the last minute of cooking, add the asparagus pieces in to blanch. Drain.
Melt the second amount of butter in the frying pan. Add the cheese, stock and milk. Whisk until smooth. Add back the mushroom mixture. Add the drained pasta & asparagus, cook for 5 minutes.