• Start by peeling and chopping potatoes for the topping and boiling until tender. As the potatoes are boiling, start on the filling.
• Grease the casserole dish well with butter.
• Pre-heat oven to 180 degrees celsius / 360 degrees fahrenheit, fan-forced.

Tuna Filling

• Make a white sauce: Melt butter in a saucepan over low-medium heat. Add the flour and cook for a few minutes or until flour starts to brown. Over low heat, add the milk slowly, stirring to combine. (Sometimes a whisk is handy here to ensure a smooth sauce). Once all the milk has been added, heat gently until mixture starts to bubble and thicken. Once thickened, remove from heat.
• Add all of the contents of the canned tuna (including brine) and other tuna filling ingredients to the white sauce. Stir well to combine, ensuring you break up any larger chunks of tuna.
• Pour mixture into prepared casserole dish and set aside.

Potato Topping

• Mash potato well, then add ⅔ of the chives and the remaining potato topping ingredients. Use potato masher to combine all of the ingredients.
• Spoon potato topping over top of tuna filling. Use the back of a metal spoon or fork to even out potato layer.
• Place into pre-heated oven for 30-40 minutes or until potato starts to turn a golden brown colour in parts.
• Garnish with remaining chives and serve warm with potato chips/crisps (which are used to scoop out bite-sized portions of pie).