I still remember the first time I pulled this Celeriac, Leek and Mushroom Pie Recipe out of the oven and watched the pastry puff up into golden, flaky layers. The smell of tarragon and melted cheddar filled my kitchen, and I knew this one was a keeper.

It’s the kind of dish I make when I want something warm, hearty, and a little bit fancy without much fuss. Jam Buttered Toast Cookie Recipe is another simple treat to enjoy when you’re in the mood for something homemade. If you’ve never cooked with celeriac before, this recipe is the perfect place to start.

Cooking Time

Prep Time: 20 minutes
Cooking Time: 1 hour
Total Time: 1 hour 20 minutes (plus cooling time)

Ingredients

10g dried porcini mushrooms – these bring a deep, savory richness, so don’t skip them
3 leeks, rinsed and thinly sliced – forms the sweet, mellow base of the filling
1 large celeriac, about 750g, peeled and cubed – the earthy, hearty star of the pie
6 tablespoons extra virgin olive oil – for softening the vegetables until tender
1 teaspoon fine sea salt – helps draw out moisture as the vegetables cook
4 garlic cloves, crushed – adds that essential savory backbone
250g chestnut mushrooms, sliced – use fresh mushrooms, never canned, for the best bite
1 teaspoon ground black pepper – adds a gentle warmth to the whole filling
3 tablespoons Dijon mustard – brings a tangy sharpness that balances the cream
100g extra mature cheddar, grated – grate it fresh for the smoothest, creamiest melt
100ml double cream – makes the filling silky and rich
½ x 20g pack tarragon leaves, picked – its subtle aniseed note is what makes this pie special
1 medium egg, beaten – for brushing the pastry to a shiny, golden finish
320g ready-rolled puff pastry – the flaky, golden lid that pulls it all together

Note: This recipe serves 6, so double the quantities if you’re cooking for a larger group.

Equipment You Need

Large saucepan – for softening the leeks, celeriac and mushrooms
Sharp knife and chopping board – for prepping all the vegetables
Pie or gratin dish, about 20x32cm – to hold the filling and pastry topping
Pastry brush – for brushing egg wash over the pastry
Mixing bowl – for soaking the dried porcini mushrooms
Rolling pin – handy if you need to adjust the pastry to fit your dish

How to Make Celeriac, Leek and Mushroom Pie?

I know this looks like a long ingredient list, but the method itself is really simple. It comes together in three easy stages: prepping, cooking the filling, and topping it with pastry. Here’s exactly how I do it every time.

Soak the Porcini and Prep Your Vegetables

Start by placing the dried porcini in a bowl and covering them with 250ml of just-boiled water. Let them soak for about 30 minutes while you slice the leeks and peel and cube the celeriac. This soaking step is what gives the filling its deep, savory flavor later on.

Cook the Vegetable Filling

Heat the olive oil in a large saucepan and add the leeks, celeriac and salt. Cook for about 10 minutes until the leeks soften, then stir in the garlic, chestnut mushrooms and chopped porcini. Pour in the reserved porcini broth, cover, and simmer until the celeriac turns soft.

Assemble and Bake the Pie

Stir the pepper, mustard and cheddar into the filling until melted, then fold in the cream and tarragon. Tip everything into your pie dish, top with the puff pastry, brush with egg, and cut a few slits for steam. Bake until the pastry turns golden and puffed.

Additional Tips for Making This Recipe Better

I’ve made this pie more times than I can count, and I’ve picked up a few tricks along the way.

I always grate my own cheddar instead of buying pre-shredded, since it melts so much smoother into the sauce.
I let the filling cool slightly before adding the pastry, otherwise the base can go soggy.
I use fresh tarragon whenever I can find it, because the flavor is so much brighter than dried.
I crimp the pastry edges firmly with my fingers so the filling doesn’t leak out while baking.

Common Mistakes to Avoid

I once skipped soaking the porcini properly, and the filling ended up missing that deep umami flavor I love, so I never rush this step now.
I forgot to cut steam slits in the pastry once, and the bottom turned soggy, so I always remember to add two or three now.
I’ve overcooked the celeriac before, which made the filling mushy, so I keep an eye on it and pull it off the heat as soon as it’s just tender.
I tried using pre-grated cheese once, and it didn’t melt nearly as smoothly, so I stick to grating it fresh.
I’ve rushed the cooling time before assembling the pastry, and it made the pastry base go limp, so I give it a few extra minutes to cool now.

How to Serve Celeriac, Leek and Mushroom Pie?

I love slicing this pie into thick wedges and serving it straight from the dish while the pastry is still crackling. A simple green salad with a sharp vinaigrette works beautifully alongside it, cutting through the richness of the filling. For a heartier meal, I’ll add a side of buttery mashed potatoes or steamed greens.

A few extra tarragon leaves scattered on top just before serving make it look as good as it tastes. For a light sweet finish after this rich meal, you can also enjoy a Fresh Apricots With Goat Cheese Orange Honey Walnut Syrup Recipe.

Variations

Swap the cheddar for a dairy-free cheese alternative if you want a plant-based version.
Use a shortcrust pastry base and top instead of puff pastry for a more traditional pie feel.
Add a handful of spinach or chard to the filling for extra greens and color.
Try smoked cheddar in place of regular cheddar for a deeper, smokier flavor.
Skip the mustard if you prefer a milder, creamier filling without the tang.

Nutritional Information

Here’s roughly what you can expect per serving of this pie.

Calories: 568 kcal
Protein: 13g
Carbohydrates: 28g
Fat: 43g

Make Ahead and Storage

You can prepare the filling up to a day in advance and keep it covered in the fridge until you’re ready to top it with pastry and bake.

Leftover pie keeps well in the fridge for up to 3 days. Reheat individual portions in the oven at a moderate temperature until warmed through, since this keeps the pastry crisp.

This pie also freezes well before baking. Wrap the assembled, unbaked pie tightly and freeze for up to 2 months, then bake straight from frozen, adding extra time as needed.

Why You’ll Love This Recipe

This pie has earned a permanent spot in my dinner rotation, and here’s why I think you’ll love it too.

It’s endlessly comforting. The creamy, cheesy filling under flaky pastry feels like the ultimate cozy dinner.
It’s easy to make ahead. You can prep the filling early and just bake it when you’re ready to eat.
It’s naturally vegetarian. Everyone at the table can enjoy it without any substitutions needed.
It’s easy to customize. You can swap ingredients around to suit what you have or what you’re craving.
It reheats beautifully. Leftovers taste just as good the next day, which makes it great for meal prep.

FAQs

What exactly is a celeriac mushroom pie?

It’s a savory pie made with tender celeriac and mushrooms cooked in a creamy, cheesy sauce, topped with puff pastry. It’s a warming, vegetarian main that works well for chilly evenings.

Is this a vegetarian leek and mushroom pie?

Yes, this recipe is fully vegetarian. The leeks and mushrooms combine with celeriac in a rich, cheesy sauce, so there’s no meat needed to make it satisfying.

How does this compare to a BBC Good Food style leek and mushroom pie?

It’s similar in spirit, since both use leeks and mushrooms as the base, but this version adds celeriac and tarragon for extra depth and a slightly different texture.

Can I turn this into a celeriac mushroom and cheddar pie?

This recipe already includes cheddar, so you’re covered. You can add even more cheese on top of the filling before adding the pastry if you want it extra cheesy.

Any tips for a beginner trying a mushroom and leek pie recipe for the first time?

Take your time softening the leeks and celeriac, and don’t skip soaking the porcini. Those two steps build most of the flavor in this dish.

What is a celeriac pithivier, and is it different from this pie?

A pithivier is a round, domed pastry parcel usually made with two pastry sheets sealed together, while this pie uses a single pastry lid over a filling in a dish. They share similar flavors but different shapes and techniques.

Ash Tyrrell