Mix and roll out a pie crust and form on the bottom of a pie shell (my favorite, or use a preformed store bought one.
If you want my pie crust recipe look at the apple pork pie recipe.
Prick bottom with a fork then bake at 425 degrees for 10 minutes.
Meanwhile, in a frying pan saute the 1 tbsp of butter and sliced mushrooms.
Put in spinach at the end just long enough for it to wilt.
Layer the slices of soft swiss cheese with the hard swiss cheese, and then grate together. (This works so much better than having a pile of soft cheese and a pile of hard cheese. The quiche sets up more uniformly this way.)
On the bottom of the pie crust sprinkle 3/5ths of the cheese.
Layer the spinach and mushrooms and then the rest of the swiss cheese on top.
Beat your eggs, salt and pepper, and half and half well and pour on top.
If your pie plate is fairly large, you might want to mix up another egg and ⅓ cup of half and half to top it off.
Bake an additional 30-45 minutes until done. Let set for 5 minutes before serving.