Golden Spinach Strata
2 tablespoons unsalted butter
1 medium onion, sliced
5 cups lightly packed cubed (3/4" to 1" cubes) challah or another egg bread
2 cups lightly packed shredded butternut squash (from about 3/4 pound squash)
One 9- to 10-ounce package frozen chopped spinach, thawed and squeezed dry
3 1/2 cups half-and-half
1 teaspoon kosher salt
1/4 teaspoon freshly ground pepper
2 cups lightly packed shredded aged Gouda cheese (6 ounces)
The secret ingredient in this breakfast casserole is butternut squash. The shredded squash blends into this egg puff and looks almost like cheese. It lends a slightly sweet, nutty flavor to this fall dish. I like to use a challah loaf here because the rich egg bread is firm enough to hold its shape during baking, but is light enough to complement the other ingredients. Look for an aged Gouda cheese, such as Mona Lisa. It lends a buttery, caramel note to the dish. If you can't find it, Gruyere is also good. You'll need to assemble this dish the night before.
Lightly butter a 13x9-inch glass baking dish or coat with nonstick spray. Melt the butter in a medium skillet over medium heat. Add the onion and cook for 8 to 10 minutes or until the onion is golden brown, stirring occasionally.
Meanwhile, toss the challah and squash together in a large bowl and arrange in the baking dish. Scatter the browned onion and the spinach over the bread mixture. Whisk the eggs in a large bowl until blended and smooth. Whisk in the half-and-half, salt, and pepper until combined. Pour the egg mixture over the bread and vegetables. Make sure all of the bread mixture is moistened, pressing on the bread cubes if necessary to coat with the egg mixture. Sprinkle the cheese over the top. Cover with plastic wrap and refrigerate overnight.
When ready to bake, preheat oven to 350°F. Remove the plastic and let the strata sit at room temperature while heating the oven. Bake for 50 to 60 minutes or until the strata is puffed, the top is golden brown, the center is set, and a knife inserted in the center comes out moist but with no milky reside. Let sit for 5 minutes before cutting.
Recipe from "Chicken and Egg" by Janice Cole.