French Baguette Casserole - cooking recipe

Ingredients

12 ounces fresh spinach, rinsed well
2 loaves French baguettes
1/4 cup olive oil, plus more for sauteing
1 red onion, sliced thinly
8 ounces sliced mushrooms
1 1/2 teaspoons ground cumin
4 ounces gruyere cheese, grated
6 eggs
2 cups milk
salt & fresh ground pepper, to taste
grated nutmeg (optional)

Preparation

In a medium stockpot, bring 1 & 1/2 cups water to a boil. Add spinach, cooking 2 minutes. Drain in colander; press out any remaining water by placing spinach in a cotton, kitchen towel and squeezing out moisture. Chop roughly and set aside.
On an angle, cut French baguette bread into 1/2″ thick slices. Using a basting (or pastry) brush, lightly oil both sides of each slice with olive oil. Spray your favorite casserole dish (13x9x2″ or 11x9x3″) with non-stick cooking spray, and line the bottom of dish (and sides if necessary) with the prepared bread, slightly layering and overlapping the slices.
Over medium heat, warm a few tablespoons of olive oil in a large skillet. Add the onion and saute until fragrant, about 40 seconds. Add sliced mushrooms and cook 5 minutes more, stirring frequently. Add ground cumin and spinach, stirring to combine.
Layer cooked onion/mushroom/spinach mixture over the bread, spreading evenly. Layer shredded Gruyere over the vegetables, spreading evenly. In a medium-sized bowl, whisk eggs and milk with salt and pepper to taste. Gently and evenly, pour egg mixture over the layered bread and vegetables in casserole dish. Cover and place in refrigerator for at least 1 hour to let the custard mixture absorb into the bread.
After 1 hour, preheat oven to 375 degrees F and remove casserole from refrigerator. Uncover and bake for approximately 40-45 minutes, or until cheese begins to turn golden brown and just crispy. Knife inserted near center should come out moist, but relatively clean.
Remove from oven, allow casserole to cool slightly, then cut into portions for serving. If desired, garnish individual portions with a pinch of ground nutmeg. Serve warm with green salad or fresh fruit.