Notes: I used 3/4 of an old baguette, but you can use any kind of bread you like. I followed this basic ratio recipe: 1 part milk + 1 part egg + 1 part cheese + 1 part add-ins (optional) + 2 parts bread that I found on Epicurious and found it worked perfectly. This strata is custardy and creamy in the middle with bits of crispy, craggy bread on top.
Lightly butter an oven safe baking dish and set aside. You can use an 8×8 inch dish or several mini ones, it won’t affect the baking time.
Slice one of the mushrooms (for the top of the strata) and dice other mushroom. In a sauté pan, heat up the butter over medium heat. Add the sliced mushrooms and stir to coat with butter. Cook, stirring and flipping occasionally, until the mushrooms are golden. Remove from the pan and set aside. Add more butter to the pan if needed and cooked the diced mushrooms until golden. Remove and set aside to cool completely.
In a large bowl, toss the bread cubes with 1 cup of cheese, the cooled mushrooms, and dill. Place in the prepared pan.
In a large liquid measuring cup (or medium bowl), whisk together the milk, eggs, dijon, salt and pepper. Pour over the strata and top with the remaining 1/2 cup of shredded mozzarella. Wrap with plastic wrap and place in the fridge overnight so the bread can absorb the custard. Or, if you’re eating it right away, let it sit for 30 minutes so the bread can absorb the custard.
When you’re ready to eat, set the oven for 350°F. If you put the strata in the fridge, pull it out and let it come to room temperature for 30 minutes.
Bake the strata, uncovered, until puffy, golden brown, and cooked through, about 45 – 55 minutes. If the top starts browning too much, cover lightly with foil. Remove from the oven, let set for 5 minutes and enjoy!