8 slices firm textured bread, not sourdough
2 tablespoons butter, divided
1 medium onion, diced
1/2 teaspoon dried oregano
1/2 teaspoon dried thyme leaves
8 ounces fresh mushrooms, chopped unevenly
Salt and pepper
2 cups milk
1 teaspoon dried (powdered) mustard
Dash hot pepper sauce, such as Tabasco™
3 eggs, beaten
2 tablespoons chopped green onions
1/2 cup shredded Wisconsin Smoked Cheddar cheese
4 slices (3 ounces) diced Wisconsin American processed cheese
1/2 cup Wisconsin Parmesan cheese, shredded or grated
Trim the crusts from the bread and place half the slices in an oblong baking dish, about 10 inches in length. Cut the bread to cover the bottom of the casserole. Reserve remaining slices.
Preheat the oven to 375°F.
Melt 1 tablespoon of the butter in a deep, large skillet and add the onion. Crumble the oregano and thyme over the onion and mix. Cook the onion over low/medium heat until it is soft, about 12 minutes. Add the remaining butter and mushrooms. Stir so the mushrooms are coated. Cook the mushrooms for about 5 minutes, until tender. Season with salt and pepper.
In a large bowl, whisk the milk, dried mustard, hot pepper sauce and eggs. Stir in green onions. In another bowl, mix the cheeses.
Spoon the mushroom mixture over the bread in the casserole. Layer with half the cheese. Place remaining bread slices over and top with remaining cheese. Pour milk mixture over all. Cover with foil. Bake 20 minutes. Remove foil and bake 15 minutes longer.