Ham and Mushroom Strata

2 small onions, diced
3/4 lb. mushrooms, sliced
1 Tbsp. butter
200 g black forest ham, sliced then chopped
200g swiss cheese, grated
1 loaf light rye bread, sliced 1/2" thick
10 large eggs
1/2 cup milk
Salt
Freshly ground pepper

Heat butter in a skillet until hot. Saute onions until they begin to brown. Add mushrooms and saute until liquid evaporates. Cool.
Lightly grease a large shallow casserole dish (9" by 13") with butter.
Line bottom of dish with one layer of rye bread.
Combine the mushroom mixture, ham and 1/3 of cheese. Spread evenly over bread slices and season with pepper.
Cover with another layer of bread slices.
In a medium bowl, beat together eggs, milk, 1 tsp. salt and 1/4 tsp. pepper. Pour evenly over bread slices.
Cover casserole dish with plastic wrap and refrigerate for 2 hours or preferably overnight.
Bake at 350 degrees F for 50 to 60 minutes or until middle is puffy.
Sprinkle with remaining cheese and bake for another 5 minutes or until cheese melts.

Makes 6 to 8 servings

Variations:
For vegetarian strata, omit ham, use more cheese and season with more salt and pepper.

This is a great recipe for leftovers: use any bread, meat, vegetable (as long as they're not too soggy) and cheese combination you like.