Prep time: 30 minutes
Cook time: 1 hour 10 minutes
Yield: 6 servings

Ingredients:

  • 2 Tb. unsalted butter
  • 1 bunch leeks, thinly sliced
  • 3 celery stalks, minced
  • 3 pints mushrooms, minced
  • 2 garlic cloves, minced
  • 4 cups spinach
  • ¼ cup chopped fresh parsley
  • 2 tsp. chopped fresh rosemary
  • 1 tsp. chopped fresh thyme
  • Salt and freshly ground black pepper, to taste
  • 2 sheets store-bought puff pastry
  • 1 egg
  • Sea salt flakes, as needed for finishing

Directions:

  • 1

    Start by heating your oven to 400°F and lining a baking tray with parchment paper.

  • 2

    Melt butter in a sizable frying pan over medium heat, then add leeks and celery, cooking them until they're soft, which should take about 3 to 4 minutes.

  • 3

    Next, mix in the mushrooms and cook them until they're browned and have released their moisture, shrinking in size, for about 8 to 10 minutes.

  • 4

    Add garlic and cook for a minute until it emits a pleasant aroma. Gradually add spinach, stirring until it fully wilts.

  • 5

    Mix in parsley, rosemary and thyme, then season with salt and pepper according to your taste. Let this mixture cool down. (You can prepare this filling up to two days ahead and store it in the fridge in a sealed container.)

  • 6

    On a surface dusted with flour, carefully unfold one puff pastry sheet and roll it to a thickness of about ⅛ inch. Move it onto your prepared baking sheet.

  • 7

    Spread the filling on the pastry sheet, ensuring a 1-inch border. Dampen these edges with water using a pastry brush.

  • 8

    Roll out the second puff pastry sheet on a floured surface to the same thickness as the first. Gently place it over the filling and press along the edges with your fingers to seal.

  • 9

    Trim any uneven edges with a knife, then use a fork to crimp around the edges.

  • 10

    In a small dish, mix the egg with a tablespoon of water, and brush this egg wash over the top of the pastry.

  • 11

    Cut diagonal lines about 1 inch apart across the pastry using a paring knife. Turn the tray 45 degrees and repeat, creating a crosshatch design.

  • 12

    Sprinkle the top with flaky salt, then bake in the oven for 40 to 50 minutes until it turns golden brown. Allow it to cool for at least 15 minutes before cutting. Best served warm.