Ingredients:

  • 450 g (16 oz) medium shell pasta (Conchiglie) or elbow macaroni
  • 2 tsp (10 g) Sea salt, for boiling water
  • 55 g (4 tbsp / ½ stick) Unsalted butter
  • 55 g (½ cup) All-purpose (plain) flour
  • 800 ml (3 ¼ cups) Whole milk, warmed slightly
  • ½ medium Yellow onion, finely diced (about 80 g)
  • 1 tbsp Dijon mustard
  • 1 tsp Worcestershire sauce
  • ½ tsp Black pepper, freshly ground
  • ¼ tsp Nutmeg, freshly grated (optional)
  • 2 x 140 g (5 oz) cans Tuna, packed in water or oil, very well drained
  • 280 g (10 oz / about 2 ½ cups) Sharp Cheddar cheese, grated
  • 50 g (½ cup) Parmesan cheese, finely grated (divided use)
  • 60 g (1 cup) Panko breadcrumbs
  • 30 g (2 tbsp) Unsalted butter, melted (plus extra for greasing)

Instructions:

  1. Preheat oven to 200°C (400°F). Lightly grease a 9x13 inch casserole dish. Bring a large pot of salted water to a rolling boil. Add pasta and cook until al dente (about 1 minute less than package directions). Drain the pasta immediately and set aside.
  2. In a medium saucepan, melt the 55g of butter over medium heat. Add the diced onion and sauté gently until soft and translucent (about 5 minutes). Whisk in the flour and cook, stirring constantly, for 1–2 minutes to create the roux.
  3. Gradually whisk in the warmed milk, adding small amounts at a time, until the sauce is smooth and thickens sufficiently to coat the back of a spoon (about 5–7 minutes). Remove from heat. Stir in the Dijon mustard, Worcestershire sauce, black pepper, and nutmeg. Add the 280g of grated Cheddar and half of the Parmesan (25g). Stir until the cheese is completely melted and the sauce is glossy.
  4. Gently fold in the well-drained tuna into the sauce. Pour the finished sauce mixture over the cooked pasta in the colander. Stir gently until every piece of pasta is coated. Pour the entire mixture into the prepared casserole dish, spreading evenly.
  5. In a small bowl, combine the Panko breadcrumbs, the remaining 25g of Parmesan, and the 30g of melted butter. Mix well. Sprinkle the Panko mixture evenly over the pasta filling. Bake for 20–25 minutes, or until the sauce is bubbling and the topping is deep golden brown and crisp. Let the casserole rest for 5–10 minutes before serving.