Walnut Crust

  • 2 tablespoons butter
  • 1/4 cup panko breadcrumbs
  • 1/4 teaspoon salt
  • 1/4 teaspoon freshly ground black pepper
  • 3/4 cup California walnuts, finely chopped


  • 4 tablespoons butter
  • 1 medium onion, finely chopped
  • 225g cremini or baby bella mushrooms, sliced
  • 1/4 cup all-purpose flour
  • 2 cups whole milk
  • 1 cup vegetable broth
  • 225g large pasta shells
  • 3 cans (140g) water packed tuna, drained and flaked
  • 1 cup frozen petite peas
  • 2 tablespoons chopped fresh flat leaf parsley, plus additional for garnish
  • 2 cups shredded sharp white cheddar cheese, divided


  1. To prepare the crust, melt butter in a large skillet over medium heat. Add breadcrumbs, salt and pepper and cook, stirring frequently, for 2 to 3 minutes or until breadcrumbs are golden brown. Transfer to a medium bowl and stir in walnuts; set aside.
  2. Preheat the oven to 160°C and lightly grease a 2 1/2-quart shallow baking dish.
  3. To prepare the casserole, cook pasta in boiling water until al dente. Drain well and set aside.
  4. While pasta is cooking, melt butter in a very large skillet over medium heat. Add onion and cook, stirring occasionally, for 5 to 7 minutes or until slightly softened and translucent. Increase heat to medium-high and add mushrooms and salt. Cook for 6 to 8 minutes more or until vegetables are tender and lightly browned.
  5. Stir in flour and cook for about 1 minute. Gradually stir in milk and vegetable broth and bring to a gentle boil. Reduce to a simmer and cook, stirring frequently, for 5 minutes or until slightly thickened.
  6. Stir pasta into vegetable mixture with tuna, peas and parsley. Remove from heat and stir in half the Cheddar cheese. Season with salt and pepper.
  7. Spread into a prepared baking dish and sprinkle with remaining cheese. Cover with walnut mixture.
  8. Bake for 25 to 30 minutes or until bubbling on the edges and golden brown on top. Let stand 5 minutes before serving. Garnish with chopped parsley.