Leek and Mushroom Quiche

This leek and mushroom quiche is rich, cheesy, and loaded with flavour.

Using a store-bought pie shell makes it so much easier to pull together for a casual brunch or special event.

Ingredients and Substitutions

• Deep Dish Pie Shell: I used a store-bought, frozen, 9-inch deep dish pie shell. If you'd prefer to make your own shortcrust pastry, you absolutely can. I have tested this recipe with both the Tenderflake all-vegetable deep-dish pie shell and the Great Value all-vegetable deep-dish pie shell, and both worked well.
• Olive Oil: Used together with the butter to cook the leeks and mushrooms. The oil raises the smoke point of the butter, so it doesn't burn. Any neutral oil will work, like vegetable oil.
• Salted Butter: Adds richness and flavour to the filling. Use it together with the olive oil when cooking the leeks and mushrooms.
• Leek: This is the star of the filling. You may need to buy 2 leeks if they are small. Leeks have a gentle onion-like flavour that softens when they cook. Be sure to wash it well, as they tend to trap dirt between their layers.
• Cremini Mushrooms: I like the depth of flavour in cremini mushrooms, but you can substitute with white button mushrooms.
• Eggs: These form the base of the custard filling. Use large eggs.
• Heavy Whipping Cream: This gives the custard its signature rich, silky texture. In Canada, look for 35% whipping cream. American heavy cream (36%) works just as well.
• Milk: Lightens the heavy cream slightly to keep the custard from being too rich, and makes the texture fluffier. I used 2% milk, but whole milk should work, too.
• Thyme (optional): Fresh thyme is wonderful with mushrooms and leeks. Dried thyme can be used if fresh thyme isn't available. Use a pinch of dried thyme so it's not overpowering.
• Parmesan Cheese: do not substitute; the flavour won't be the same.
• Old Cheddar Cheese: Cheddar is not optional in this recipe, but the age can vary depending on your taste. I used 2-year-old Balderson cheddar for its sharp, pronounced flavour. A younger cheddar will give you a milder result.
• Nutmeg (optional): Just a small pinch adds a subtle warmth to the custard. It's a classic addition to quiche and pairs nicely with the leeks and cheese, but you can leave it out if you prefer.

This recipe has not been tested with all possible substitutions or variations. Making changes may alter the taste, texture, or overall outcome. If you try a different ingredient, please share in the comments!

See the recipe card for the complete ingredient list and recipe instructions.

Variations

Here are a couple of ways you can change up this quiche.

• Add meat: Cooked, crumbled bacon or diced ham is a lovely addition. Stir it into the filling along with the cooked leeks and mushrooms.
• Add spinach: Stir a handful of fresh spinach into the skillet at the end of cooking, just until it wilts, then add it to the filling.

How to Clean Leeks

Leeks grow in sandy soil, and dirt tends to hide between their layers, so a quick rinse isn't always enough.

To clean them properly, trim off the root end and the tough dark green tops, then cut each leek in half lengthwise.

Open up the layers and rinse thoroughly under cold running water, letting the water run between the layers to flush out any grit.

For extra insurance, finely chop the leeks, then transfer them to a bowl of cold water and swish them around. Any remaining dirt will sink to the bottom.

Lift the leeks out with your hands or a slotted spoon, leaving the grit behind, and pat them dry before cooking.

How to Make Leek and Mushroom Quiche

Cook the leeks and mushrooms well before adding them to the filling. They release a lot of moisture that could make the quiche watery if they go in raw.

Please see the recipe card below for the full instructions; this is just a visual guide to help you successfully make this recipe.

Step 1: Use a fork to prick holes in the unbaked pie shell.

Step 2: Add a piece of parchment and pie weights (or dried beans) inside the unbaked pie shell. Bake for about 10 minutes.

Tips for Success

• Cook the leeks and mushrooms until all of the moisture has cooked off. If there's too much liquid in the skillet, it can make the filling watery.
• Let the leek and mushroom mixture cool for a few minutes before adding it to the eggs and cream. Adding a very hot mixture too quickly can start to scramble the eggs.
• Bake the quiche on a sheet pan/baking sheet. This makes it easier to take the quiche in and out of the oven, and makes any drips easier to clean up.
• To check if the quiche is done, give the pan a gentle shake. The edges should be set, but the very centre can have a slight wobble. It will firm up as it cools.
• If the crust edges are browning too quickly before the filling is set, cover them loosely with strips of foil.
• This quiche tastes great at room temperature, which makes it a good option for prepping ahead of an event.

Serve With

This quiche is a great fit for a relaxed brunch or a casual tea party. Here are a few things that pair nicely with it:

• A good cup of tea. If you're new to loose leaf, start with my beginner's guide to loose leaf tea or my post on how to brew loose leaf tea
• A fresh baby spinach salad
• Pimento cheese tea sandwiches
• Smoked salmon tea sandwiches

Common Questions

This quiche is a great addition to an Easter brunch or Mother's Day tea menu.

If you make this quiche, I'd love to hear how it turned out! Let me know in the comments!