This is a flexible recipe for a version of shepards pie with a squash topping!  Try adding or deleting as desired the veggies involved. 

Leeks (or onions), cleaned and chopped
Carrots, peeled and chopped
Beets, peeled and chopped small
Sausage, cooked (Carmen likes chorizo)
4 cups cooked squash, seasoned with salt/pepper

Sauté leeks, carrots, beets until tender.  Add sausage and stir.  Lay in the bottom of baking dish.  Top with mashed squash and bake in 350 oven until heated through.