Ingredients:

  • 4 Tbsp (60g) Unsalted Butter (plus extra for greasing)
  • 1 medium Yellow Onion, finely diced (approx. 150g)
  • 2 stalks Celery, finely diced (approx. 100g)
  • 2 medium Leeks, thoroughly washed and sliced into thin half-moons (approx. 300g)
  • 2 cloves Garlic, minced
  • 1 tsp Fresh Thyme Leaves
  • Salt and freshly cracked Black Pepper, to taste
  • 1/4 cup (60g) All-Purpose Flour
  • 2 cups (475 ml) Turkey Stock (or low-sodium Chicken Stock), warm
  • 1 cup (240 ml) Whole Milk, warm
  • 1 Tbsp Dijon Mustard
  • 1/2 cup (120 ml) Heavy Cream
  • 1/4 cup (60g) grated Parmesan Cheese
  • 4 cups (500g) Cooked Turkey, shredded or cubed
  • 1 cup (150g) Frozen Peas (do not thaw)
  • 1 cup (100g) Panko Breadcrumbs
  • 1/2 cup (60g) Mature Cheddar Cheese, grated
  • 2 Tbsp (30g) Unsalted Butter, melted

Instructions:

  1. Prep the oven and vegetables: Preheat oven to 375°F (190°C). Lightly grease a 9x13 inch casserole dish. Dice the onion and celery, slice the leeks, and mince the garlic.
  2. Sauté Aromatics: Melt 4 Tbsp of butter in a large skillet over medium heat. Add the diced onion, celery, leeks, and thyme. Cook gently for 6–8 minutes until the leeks are tender and wilted. Add the garlic and cook for 1 minute more.
  3. Create the Roux: Sprinkle the flour over the cooked vegetables. Stir vigorously for 1–2 minutes; this cooks out the raw flour taste and forms the roux base.
  4. Whisk in Liquid: Gradually pour in the warm turkey stock while whisking constantly to prevent lumps. Once smooth, slowly whisk in the warm milk.
  5. Thicken and Season: Bring the sauce to a gentle simmer, stirring frequently, until it thickens to coat the back of a spoon (about 3–4 minutes). Remove from the heat. Stir in the Dijon mustard, heavy cream, Parmesan, and a generous seasoning of salt and pepper.
  6. Combine Filling: Add the shredded cooked turkey and frozen peas directly into the prepared cream sauce. Stir gently until everything is evenly coated. Taste and adjust seasoning if necessary.
  7. Transfer and Top: Pour the turkey mixture into the prepared casserole dish. In a small bowl, combine the Panko breadcrumbs, grated cheddar cheese, and 2 Tbsp of melted butter. Toss until uniformly coated, then sprinkle evenly over the turkey mixture.
  8. Bake and Rest: Bake for 35–40 minutes, or until the filling is bubbling hot and the crumb topping is deeply golden brown and crispy. Allow the casserole to rest uncovered for 10–15 minutes before serving.