Butternut Squash Custard with Mushrooms, Leeks, and Fontina (except not)

Adapted from the Boston Globe

2 lb butternut squash, shredded
1 lb mushrooms (original called for baby bella)
"3 medium leeks" (or some number of large leeks, or whatever), thinly sliced
a splash of olive oil
4 eggs
4 or more ounces cream cheese or some other tart milk product such as
   sour cream (original called for 8 ounces creme fraiche)
thyme (original called for one tablespoon chopped fresh; I used a
   teaspoon or so dried) 
Sage (original called for 8 fresh leaves; I used half a teaspoon
   or so ground dried)
1/4 teaspoon nutmeg
a few grinds of black pepper
1-2 cups shredded cheese (original called for fontina which was an
   incredible headache to shred; later I used cheddar)

Cook leeks and mushrooms in the splash of oil until soft

Whisk eggs, your tart milk product, and spices together in a medium
bowl. Stir in grated cheese. Mix shredded butternut squash and cooked
vegetables together in a large bowl, and mix in the egg/cheese
mixture.

Grease a 9x13 baking dish, press mixture evenly into the pan. Bake for
about an hour at 350. Original said 45 minutes, but it was way wrong.