½ loaf supermarket French or Italian bread (8 oz), sliced ½ inch thick
4 Tablespoons (1/2 stick) unsalted butter, softened, plus extra for greasing dish
4 shallots, minced
1 (10 oz) package chopped frozen spinach, thawed and squeezed dry
Salt and pepper
½ cup dry white wine
6 oz Gruyere cheese, shredded (1 ½ cups)
6 large eggs
1 ¾ cups half-and-half
Adjust oven rack to middle position and heat to 225 degrees. Spread bread over a large baking sheet and bake until dry and crisp on both sides, about 20 min per side. (Alternatively, leave the slides out overnight to dry) Spread 2 tablespoons of the butter over one side of the dried bread slices.
Melt the remaining 2 tablespoons butter in a 10-inch non-stick skillet over medium heat. Add the shallots and cook until softened, about 3 minutes. Stir in the spinach, ½ teaspoon salt, and a pinch of pepper and cook until the spinach is heated through, about 2 minutes. Transfer the spinach to a medium bowl. Add the wine to the skillet and simmer over medium-high heat until it measures ¼ cup, about 3 minutes; set aside to cool.
Grease 8 inch square baking dish with butter. Arrange half of bread, buttered-side up, in single layer in the dish and sprinkle with half of the spinach mixture and ½ cup of the Gruyere. Repeat to form a second layer with the remaining bread, spinach, and another ½ cup of the gruyere. Whisk together the eggs, reduced, wine, half-and-half, 1 teaspoon salt, and ½ teaspoon pepper until smooth, then pour evenly over the top. Cover the surface with plastic wrap and weigh it down. (with cans or sugar etc) Refrigerate at least 1 hour or overnight.
Adjust oven to middle position and heat oven to 325 degrees. Meanwhile, allow strata to stand at room temperature for 20 minutes. Remove the weights, uncover the strata, and sprinkle with the remaining ½ cup gruyere. Bake until both the edges and the center are puffed and the edges have pulled away slightly from the sides of the dish, 50 to 55 minutes. Cool on a wire rack 5 minutes before serving.
VARIATION: BREAKFAST STRATA WITH SAUSAGE, MUSHROOMS, AND MONTERY JACK
Omit the spinach and substitute 1 ½ cups shredded Monterey Jack cheese for the Gruyere. Brown breakfast sausage, about 4 minutes. Stir in the shallots and cook until soft. Stir in 8 ounces white button mushrooms, sliced, and continue to cook until mushrooms no longer release any liquid, about 5 minutes. Transfer mixture to medium bowl and season with salt and pepper to taste. Return the skillet to medium heat, add the wine, and continue to simmer as directed in step 2. Substitute the sausage mixture for the spinach mixture when assembling the strata.