Ingredients
Mornay sauce
- 50 g butter
- 40 g plain flour
- 500 ml whole milk
- 100 g mature cheddar, grated
- 1 tsp English mustard powder
- ½ tsp salt
- ¼ tsp white pepper
Tuna and assembly
- 555 g tuna in springwater, drained
- 150 g frozen peas
- 1 small brown onion, finely diced
- 40 g panko breadcrumbs
- 25 g butter, melted
- 30 g parmesan, finely grated
- 1 tbsp fresh parsley, chopped (optional)
Method
Make the mornay sauce
Preheat oven to 200°C fan-forced.
Melt 50g butter in a medium saucepan over medium heat. Once foaming, add flour and stir constantly for 1 minute to form a smooth paste (roux).
Gradually pour in milk, whisking continuously to avoid lumps. Keep whisking until the sauce is smooth and begins to thicken, about 4–5 minutes.
Stir in grated cheddar, mustard powder, salt and white pepper. Remove from heat and taste; adjust seasoning if needed.
Combine and assemble
In a 25cm baking dish, combine drained tuna, frozen peas and diced onion. Pour mornay sauce over and fold gently until evenly combined.
In a small bowl, mix panko, melted butter and parmesan until the breadcrumbs are evenly coated. Scatter over the top of the tuna mixture.
Bake for 12–15 minutes until the topping is deeply golden and the filling is bubbling at the edges.
Finish and serve
Remove from oven and rest for 2 minutes. Scatter fresh parsley over the top if using.
Serve straight from the dish with a green salad or steamed greens on the side.




