Ingredients:

18 slices firm white bread (such as sourdough), crusts removed
8 ounces prosciutto, thinly sliced (bring to room temperature in order to separate slices easily)
8 ounces goat cheese, crumbled
6 ounces provolone cheese, grated (or use sliced)
¼ cup chopped green onions
6 Tablespoons thinly sliced fresh basil
7 large eggs
2 ½ cups milk
1 Tablespoon Dijon mustard
½ teaspoon salt
3 Tablespoons butter, melted

Instructions:

1. Line bottom of 13 X 9 X 2 inch glass baking dish completely with one layer of bread, cutting some slices to fit. 

2. Arrange half of the prosciutto slices evenly over the bread.  Sprinkle half of the goat cheese and half of the provolone over.  Sprinkle with half of the green onions and half of the basil.  Top with a second layer of bread.  Layer remaining prosciutto, goat cheese, provolone, green onions, and basil atop bread.  Cut remaining bread into ¼ inch cubes.  Sprinkle over top.

3.Whisk eggs, milk, mustard and salt in bowl.  Season with pepper.  Slowly pour egg mixture over strata.  Press down on bread with spatula.  Drizzle melted butter over strata.  Cover and refrigerate over night.
   
(If using a deeper pan, eggs and milk may be increased to fill pan more generously.  In this case, whisk an additional 2 eggs, 1 cup milk, ¼ tsp. mustard and a dash of salt and pour over strata.

4. Preheat oven to 350 degrees.  Uncover strata and let stand at room temperature 30 minutes.  Bake until center is set, about 1 hour.  Remove from oven.  If a more golden top is desired, put under broiler for about 30 seconds.

5. Cut into squares and serve. 
Serves 6 to 8 as a main course.