Sausage Cheese Sauce for Pasta

Okay this recipe is mostly my own invention.  I based it on the sauce from the chef in the video below.  Of course I had to make substitutions since this was a spur of the moment thing and I didn't have the energy to go shopping for anything fancy.

Ingredients
Makes enough sauce to cover gnocchi for 3 servings

1-2T olive oil
2-3 shallots or 1/2 a small yellow onion chopped fine
1c coarsely sliced crimini mushrooms (baby portabellos)
~1/2 lb of sweet Italian sausage meat sans casing (I had one large link left over from Baked Ravioli)
1c peas
generous pinch salt
generous pinch pepper
1/2c white wine (Pinot Grigio according to chef but I use white cooking wine from the supermarket)
1c half and half
3/4 Gruyere cheese coarsely grated (chef used 3 fat tablespoons of Gorgonzola)
1/2 Parmesan cheese coarsely grated
3 large leaves of fresh sage coarsely chopped

1. Saute onion and mushrooms in oil until soft
2. Add sausage meat.  Break up into small pieces while cooking.  Saute until brown.
3. Add salt and pepper.
4. Add wine.  Deglaze pan.  Boil wine off.
5. Add half and half, cheeses and sage.  Boil until thickened.
6. Add pasta to heat through.
7. Serve with extra Parmesan sprinkled on top.