Cheesy Leek & Potato Pie Recipe

Prepare potatoes

Place diced potatoes in a pot and cover with cold salted water. Bring to a simmer and cook until just tender, about 8–10 minutes. Drain and set aside to steam-dry for 2–3 minutes, then return to the pot off heat.

Cook leeks & onion

While potatoes cook, heat 1 tablespoon olive oil and 2 tablespoons butter in a large skillet over medium heat. Add sliced leeks and diced onion. Season with 1/2 teaspoon salt and 1/4 teaspoon pepper. Sauté, stirring occasionally, until soft and beginning to caramelize, about 8–10 minutes. Add minced garlic during the last 1 minute and cook until fragrant. Remove from heat.

Make a cheesy white sauce

In the skillet used for the leeks (wipe out excess if needed), melt remaining 2 tablespoons butter over medium heat. Whisk in 2 tablespoons flour and cook for 1–2 minutes to remove raw flour taste. Gradually whisk in 1 cup milk and 1 cup heavy cream, bringing to a gentle simmer until thickened, about 3–5 minutes. Stir in 1 cup grated cheddar, 1 cup grated Monterey Jack, and 1 tablespoon grated Parmesan until melted and smooth. Season with remaining 1 teaspoon salt, 3/4 teaspoon pepper, 1 teaspoon thyme, and 1/4 teaspoon nutmeg (if using). Taste and adjust seasoning.

Combine with vegetables

Fold the cooked potatoes and the sautéed leeks/onions into the cheese sauce gently, making sure potatoes stay mostly intact. Heat mixture for 1–2 minutes so flavors combine. Remove from heat and let cool slightly (5 minutes).

Preheat oven and prep pastry

Preheat oven to 400°F (200°C). Lightly oil or butter a 9-inch (or 8x8) pie dish or ovenproof skillet. Unfold the puff pastry on a lightly floured surface and, if necessary, trim to a circle or square slightly larger than the dish so edges can tuck down.

Fill pie

Spoon the cheesy potato-leek filling into the prepared dish, smoothing the top. Sprinkle the remaining 1 tablespoon Parmesan over the filling for a little extra crispness at the edge (optional).

Top with puff pastry

Drape the puff pastry over the filling. Tuck and fold the edges down into the dish to create a neat seal; trim excess if needed. Beat the egg with 1 teaspoon water and brush the pastry lightly with the egg wash. Using a sharp knife, make 2–4 small slits in the top to vent steam. Optionally, sprinkle a pinch of sea salt and a few additional thyme leaves on top.

Bake

Bake in the preheated oven for 25–30 minutes until the pastry is puffed and deep golden brown and the filling is bubbling at the edges. If pastry browns too quickly, tent loosely with foil for the last 5–10 minutes.

Rest & serve

Remove from oven and let rest for 10 minutes to set the filling. Serve warm, sliced into wedges. Leftovers can be reheated in a 350°F (175°C) oven for 12–15 minutes.