Chicken, Leek and Tarragon Pot Pie

Ingredients

• Beurre manié

  • 3 tbsp unsalted butter, softened
  • 1/4 cup (40 g) unbleached all-purpose flour

• Filling

  • 4 tsp cornstarch
  • 1/2 cup (125 ml) milk
  • 3 cups (285 g) leeks, thinly sliced
  • 2 tbsp unsalted butter
  • 2 1/2 cups (625 ml) chicken broth
  • 1 cup (160 g) russet potatoes, peeled and diced
  • 1 1/2 cups (255 g) cooked chicken, diced (about 1/2 store-bought roasted chicken)
  • 3 tbsp tarragon leaves, finely chopped (see note)

• Dough

  • 2 cups (300 g) unbleached all-purpose flour
  • 1/2 tsp salt
  • 1 cup (225 g) cold unsalted butter, thinly sliced
  • 2/3 cup (150 ml) ice water

• Egg Wash

  • 1 egg yolk
  • 2 tbsp (30 ml) milk