3leeks, large, trimmed and thinly sliced and cleaned (white & light green parts)
1bell pepper, small, orange or red, diced
2cupsham, diced cooked
2tablespoonsall-purpose flour
1 1/2cupswhole milk, or half-and-half
1tablespoonDijon mustard
1/3cupGruyere cheese, shredded
1/3cupgrated Parmesan cheese
Salt and black pepper, to taste
1tablespoonchopped fresh parsley
1sheet puff pastry, about 8 ounces, thawed
1egg, beaten (for egg wash)
Instructions
Cook the vegetables: In a large skillet or saucepan, melt the butter over medium heat. Add the leeks and bell pepper. Sauté until very soft and fragrant, about 8–10 minutes. Don’t rush this step—soft, sweet leeks are key.
Add the ham: Cook another 2 minutes to warm through.
Make the sauce: Sprinkle the flour over the mixture and stir well to coat. Cook for 1 minute, then gradually whisk in the milk or half-and-half. Bring to a simmer. Reduce the heat to low and simmer for 3 to 4 minutes, stirring often, until the mixture thickens into a creamy sauce.
Add flavor: Stir in the Dijon, Gruyère, and Parmesan until melted and smooth. Season to taste with salt, black pepper, and parsley. If the mixture is too thick, add a bit more milk. Let the filling cool for 10 minutes.
Assemble the pie: Pour the filling into your pie plate or baking dish and smooth the top. Roll the puff pastry out and cut it into a circle an inch or two larger than the pie dish. Place it on the filling, trimming or tucking the edges as needed. Place the pie in the fridge for about 15 minutes while you heat the oven to 400°F (200°C).
Egg wash: Cut slits in the top of the pastry and brush it with the beaten egg.
Bake: Bake for 18 to 22 minutes, or until the pastry is puffed and deep golden brown.
Rest: Let the pie rest for at least 10 minutes before serving.