Another do ahead casserole. Great for a buffet, especially around Cristmas , the colored peppers show through. If you wish lightly saute the peppers with the onion and mushrooms. I prefer them crisp.Nicely flavored combination.
These are the ultimate party potato because you can put it together in advance. The guests will oooh and aaah at the stunning presentation. Prep and cook time does not include time to make the mashed potatoes.