Easy Make-Ahead Potato and Mushrooms Casserole

Potato Mushroom Casserole is a dish that can be served either as a side dish or as a main course, depending on the size of the portion you decide to serve. This is a variation of the classic casserole made only with potatoes; in this preparation, the mushrooms add a delicate touch to the flavor of the dish, making it even more irresistible.

What is Potato Mushroom Casserole?

Potato mushroom casserole is a hearty and savory dish that combines potatoes, mushrooms, onions, eggs, and cheese into a flavorful bake. The origins of casseroles can be traced back to ancient times, where they were used as a method to create a complete meal in a single dish, often using available and affordable ingredients. The word "casserole" comes from the French term for "saucepan," reflecting the dish's typical preparation method. This particular recipe, featuring a mix of potatoes and mushrooms, showcases the versatility and comfort of casseroles. It blends the earthy flavors of mushrooms with the starchy richness of potatoes, all bound together by a custard-like mixture of eggs and milk, then topped with melted cheese. This dish is a modern adaptation that highlights the enduring appeal of casseroles as a convenient, delicious, and nourishing meal suitable for any occasion.

Tips for The Best Potato Mushroom Casserole

• Use starchy potatoes like Russets for a fluffier texture, or waxy potatoes like Yukon Golds for a firmer bite. Cut the potatoes into uniform squares to ensure they cook evenly.
• Use a good melting cheese like cheddar, Gruyère, or mozzarella. Grate the cheese fresh for better melting and flavor.
• When mixing eggs, milk, and salt, combine them just until smooth. Overmixing can incorporate too much air, making the texture less creamy.
• Sauté mushrooms separately until they release and evaporate their moisture. This prevents the casserole from becoming watery.
• Sprinkle fresh herbs like parsley or chives on top before serving for a burst of color and flavor.
• Ensure the casserole doesn't stick by using a non-stick or well-greased baking dish.

Should I Soak Potatoes Before Cooking Them in The Pan?

No, you do not need to soak the potatoes before sautéing them for this recipe. Soaking is typically done to remove excess starch, but in this casserole, the starch helps bind the ingredients together.

How Do I Thicken This Casserole?

To thicken the casserole, you can add a small amount of flour or cornstarch to the egg mixture before baking, or reduce the amount of milk slightly. This will help achieve a firmer texture.

What Can I Use Instead of Cheese For The Topping?

Instead of grated cheese, you can use breadcrumbs, crushed crackers, or a dairy-free cheese alternative for the topping.

Why is My Casserole So Watery and Runny?

The casserole may be watery and runny due to excess moisture from the mushrooms, insufficient cooking time, or too much milk in the egg mixture. To prevent this, sauté mushrooms thoroughly to release moisture, ensure the casserole is baked until set, and consider reducing the milk slightly.

Can I Make This Casserole Ahead of Time?

Absolutely! Prepare and assemble it, then store it in the refrigerator for up to 24 hours before baking. Bake it just before serving for the best texture and flavor.

Can I Freeze This Casserole?

Of course! After baking, let it cool completely, then wrap it tightly in plastic wrap and aluminum foil. Freeze for up to 2-3 months. Thaw in the refrigerator overnight before reheating.

More Potato and Mushrooms Recipes!

Creamy Mushroom Scalloped Potatoes

Savory Mushroom Potato Speck Pie

Classic Potato Casserole

Spinach Mushroom Breakfast Casserole

How to Store Potato Mushroom Casserole

Store any leftovers in an airtight container in the refrigerator for up to 3-4 days. Reheat in the oven or microwave before serving.

How to Make Potato Mushroom Casserole

Start by cutting the potatoes into even tiny squares.

In a pan with oil, start sautéeing the diced potatoes and the onion until the onion turn golden. Then, add the previously sautéed mushrooms and the garlic and salt and keep frying together.

Place the cooked potatoes and mushrooms in a well greased baking pan.

In a bowl, whisk together the eggs, the milk and the salt.

Add the egg mixture to the potatoes and the mushrooms in the baking pan, and then bake in the oven at 356°F (180°C) for about 20 minutes.

Once the 20 minutes are up, take the casserole out of the oven and sprinkle with the grated cheese. Put it back in the oven for another 10 minutes.

Let it rest for some minutes, then cut into slices, serve and enjoy!