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Mushroom and Spinach Quiche in an Oat Crust

I’ll never forget the first time I tasted a truly exceptional quiche. It wasn’t at some fancy restaurant, but at a cozy farmer’s market in Vermont. The air was crisp, the leaves were turning, and a local baker had set up a stall overflowing with savory pies. One bite of her mushroom and spinach quiche, nestled in a perfectly golden crust, and I was hooked. The earthy mushrooms, the vibrant spinach, and the creamy custard all sang together in perfect harmony. I knew then I had to learn to recreate that magic at home, and this recipe is my tribute to that unforgettable autumn day.

Recipe Overview

Prep Time: 30 minutes
Cook Time: 42 minutes
Total Time: 1 hour 12 minutes
Servings: 6-8
Yield: 1 Pie
Dietary Type: Vegetarian

Ingredients

For the Crust:

1 cup oats
1/3 cup oat bran
2 tablespoons butter, chilled and cut up
3 tablespoons cold water

For the Filling:

1 cup leek, chopped
1 1/4 cups mushrooms, sliced
1 cup evaporated milk
1 ounce parmesan cheese, grated
1/2 teaspoon salt
1/4 teaspoon dill
1/4 teaspoon thyme
1/4 teaspoon black pepper
5 eggs
10 ounces spinach (if frozen, thaw and squeeze dry)
1 ounce gruyere cheese, grated (or Swiss)

Equipment Needed

9-inch pie plate
Pastry cutter or two knives
Wax paper
Rolling pin
Skillet
Large bowl
Blender
Wire rack

Instructions

Preheat your oven to 375°F (190°C). Ensure the rack is in the center position for even baking.
Prepare the Crust: In a medium bowl, combine the oats and oat bran. Cut in the chilled butter using a pastry cutter or two knives until the mixture resembles a coarse meal. The butter should be evenly distributed and in small pieces.
Gradually add the cold water, stirring just until the mixture is moist enough to hold together. Be careful not to overmix; you want a tender crust.
Form the dough into a ball on a sheet of wax paper. Cover with another sheet of wax paper. This prevents the dough from sticking to your rolling pin and makes it easier to handle.
Roll the dough, still covered with the wax paper, into a 10-inch circle. Aim for an even thickness for consistent baking.
Remove one sheet of wax paper and carefully fit the dough into a greased 9-inch pie plate. Gently press the dough into the bottom and up the sides of the plate. Remove the remaining wax paper.
Bake the crust for 7 minutes. This par-baking helps prevent the crust from becoming soggy when the filling is added.
Remove the crust from the oven and let it cool on a wire rack while you prepare the filling. This allows the crust to firm up slightly.
Prepare the Filling: Place a skillet over medium-high heat and add a bit of oil (olive or vegetable oil works well). Add the chopped leek and sauté for 2 minutes, until softened and fragrant. Be careful not to burn the leek.
Add the sliced mushrooms to the skillet and sauté for 5 minutes, until they are tender and have released their moisture. Stir occasionally to ensure even cooking.
Remove the skillet from the heat and transfer the leek and mushroom mixture to a large bowl.
In a blender, combine the evaporated milk, parmesan cheese, salt, dill, thyme, black pepper, and eggs. Process until smooth and well combined. This creates the creamy custard base for the quiche.
Add the blended mixture to the bowl with the mushroom and leek mixture and stir well to combine. Make sure all the ingredients are evenly distributed.
Add the spinach to the mixture and stir well.
Pour the filling into the par-baked oat crust. Spread the filling evenly to ensure consistent baking.
Sprinkle the grated Gruyere (or Swiss) cheese evenly over the top of the filling. This creates a beautiful golden-brown crust and adds a nutty flavor.
Bake in the preheated oven for 35 minutes, or until a knife inserted near the center comes out clean. The quiche should be set and slightly golden brown on top.
Remove the quiche from the oven and let it stand for 5 minutes before serving. This allows the filling to set further and makes it easier to slice.

Expert Tips & Tricks

Preventing a Soggy Crust: Par-baking the crust is crucial to prevent it from becoming soggy. You can also brush the bottom of the par-baked crust with a lightly beaten egg white before adding the filling to create a moisture barrier.
Getting the Perfect Custard: Don’t overbake the quiche! Overbaking can cause the custard to curdle. The quiche is done when the center is just set and doesn’t jiggle excessively.
Adding More Flavor: Consider adding a clove of minced garlic to the leeks while sautéing for extra flavor. A pinch of red pepper flakes can also add a subtle kick.
Make-Ahead Prep: You can prepare the oat crust and the filling separately a day in advance. Store them in the refrigerator until ready to assemble and bake.
Ingredient Swaps: Feel free to experiment with different types of mushrooms, such as shiitake or cremini. You can also substitute kale for spinach or use a different type of cheese, like feta or goat cheese.

Serving & Storage Suggestions

Serve the Mushroom and Spinach Quiche warm or at room temperature. Garnish with a sprinkle of fresh dill or thyme for an extra touch of elegance. It’s delicious on its own or served with a simple green salad.

To store leftovers, allow the quiche to cool completely before wrapping it tightly in plastic wrap or placing it in an airtight container. It can be stored in the refrigerator for up to 3-4 days. You can also freeze the quiche for longer storage. To reheat, bake the quiche in a preheated oven at 350°F (175°C) until warmed through, or microwave individual slices.

Nutritional Information

Nutrient	Amount per Serving	% Daily Value
Calories	327 kcal	16%
Total Fat	19g	29%
Saturated Fat	10g	50%
Cholesterol	178mg	59%
Sodium	463mg	19%
Total Carbohydrate	29g	10%
Dietary Fiber	5g	20%
Sugars	1g	N/A
Protein	14g	28%

Note: Nutritional information is an estimate and may vary based on specific ingredients and portion sizes.

Variations & Substitutions

Gluten-Free Crust: Substitute the oats and oat bran with a gluten-free oat flour blend for a gluten-free version of the crust.
Dairy-Free Filling: Use unsweetened almond milk or coconut milk instead of evaporated milk for a dairy-free option. Substitute the parmesan and Gruyere cheese with a dairy-free cheese alternative.
Seasonal Variations: Incorporate seasonal vegetables like asparagus in the spring, roasted butternut squash in the fall, or sun-dried tomatoes and zucchini in the summer.
Protein Boost: Add cooked bacon, sausage, or ham to the filling for a protein-rich variation.

FAQs (Frequently Asked Questions)

Q: Can I use pre-made pie crust for this recipe?
A: While you can use a pre-made pie crust, the oat crust adds a unique flavor and texture to the quiche that’s well worth the effort.

Q: Can I freeze the quiche?
A: Yes, the quiche freezes well. Wrap it tightly in plastic wrap and then in aluminum foil. Thaw overnight in the refrigerator before reheating.

Q: How do I prevent the crust from burning?
A: If the crust starts to brown too quickly, cover the edges with aluminum foil or a pie shield during the last 15 minutes of baking.

Q: Can I add other vegetables to the filling?
A: Absolutely! Feel free to add other vegetables like bell peppers, onions, or broccoli to the filling. Just make sure to sauté them before adding them to the quiche.

Q: What if I don’t have evaporated milk?
A: You can substitute evaporated milk with heavy cream or half-and-half for a richer custard.

Final Thoughts

This Mushroom and Spinach Quiche in an Oat Crust is more than just a recipe; it’s an invitation to savor the simple joys of home cooking. The earthy flavors, the creamy texture, and the wholesome crust all come together to create a truly satisfying dish. Whether you’re serving it for brunch, lunch, or dinner, I encourage you to give this recipe a try. Let me know how it turns out and what variations you come up with. Perhaps pair it with a crisp white wine or a refreshing iced tea. Happy cooking!

Mushroom and Spinach Quiche in an Oat Crust Recipe