Brioche Strata (Bacon, Ham, Spinach, Onions)

It was my turn to bring something into work in the morning and, as always, I had waited until the last minute to decide what to make.  The decision of what to bring is really the most dubious of tasks and one I take quite seriously. I find myself worrying about what to make.  It's got to be something new, and something relatively easy to transport.  It can't be too similar to what someone else has brought recently.  Oh, and it has got to be fabulous. 

In general, sweets are very popular.   In fact, if it's homemade then it's generally some sort of sweet treat.  The only savory options anyone ever brings are bagels.  Which is in a way strange, since there is nothing inherently 'breakfast' about cookies or brownies. Eventually after a few hours of meditation (with one or two chocolate breaks), I had come to what I thought fulfilled most of my requirements and broke some ground into the savory baking dilemma. - strata.    

**I had always assumed that strata was a savory Italian bread pudding.  Probably something about the way 'stra-ta' sounds (it is so much more fun to say with an Italian inflection).  I was surprised to find (according to Wikipedia, my source of all knowledge) that it is an American invention with the first recipe appearing  in 1902.  Seems questionable to me, but who am I to disagree with the Wiki? 

5-6 cups cubed brioche (I had used Trader Joe Brioche buns)

10 large eggs

1 quart whole milk

1 teaspoon dry mustard

1 teaspoon salt

3/4 cup frozen chopped spinach

2 cups grated Swiss cheese (I used some baby Swiss and mixed in some Gruyere)

1/2 cup caramelized onions

1 cup cubed ham

4 strips of bacon

Butter a 9x13-inch baking dish.   Prepare the filling ingredients (rendered bacon grease can be used for either caremelizing the onions or added to the brioche for a quick toast).  The cubed brioche was left out to dry on the counter top (the brioche can be lightly toast the bread until firm, but not browned to help dry it out). Put the brioche cubes in the dish and sprinkle with the cheese.  

In a large bowl, whisk together the eggs, milk, mustard and salt.  Pour the egg mixture over the bread cubes; then sprinkle the filling ingredients over the egg mixture and fold them in gently.  

Cover, and chill overnight (at least 4 hours and up to 24 hours).

Heat the oven to 350 degrees F.  

Uncover the baking dish and bake for 60 min, until the strata has browned on top and puffed up a bit.  The strata shouldn't jiggle with uncooked custard when you shake the pan.