Sausage Pasta with Walnuts and Sage Butter

I've made a dish similar to this before. It's super yummy and serves up nicely as leftovers the next day.

What you need:
1/2 box ziti or penne pasta
1 package of sweet sausage - about 6 to 8 links (casing removed)
1/2 cup walnuts (toasted)
4 tbsp Asiago cheese, shredded
1stick butter
1/2 c fresh sage, chopped or about 2 tbsp powdered sage
1/2 yellow onion, diced

What you do:
Boil your pasta. In a frying pan add diced onion and 2 tbsp butter. Saute a few minutes until onions are cooked then add the sausage. Try to crumble the sausage as you add it to the pan. You can also break it up while it's cooking. As pasta is finished drain and set aside. Add toasted nuts to the frying pan. Mix. In a separate pot melt remaining butter with the sage. Cook for 2 minutes then combine everything - butter into the sausage mixture first, then pasta. Mix well. Sprinkle with cheese and serve.