40 g butter
2 Tbsp plain flour
2 ¹/₂ cup milk
425g can tuna, drained, flaked
¹/₂ cup grated Parmesan, plus ¹/₄ cup extra for the topping
Zest of 1 lemon
Salt and pepper
1 kg potatoes, peeled and cut into 5mm slices
2 x 120g bags baby spinach leaves, chopped
1 onion, finely sliced
- Preheat oven to 180°C (160°C fan-forced). Lightly grease a 2L baking dish.
- In a medium saucepan, melt butter over high heat. Add flour and stir. Cook for 1 minute. Remove from heat and gradually mix in the milk. Stir until smooth.
- Return to heat and cook, stirring, until sauce boils and thickens. Simmer for 3 minutes.
- Stir in tuna, Parmesan, and zest. Season to taste.
- Arrange half of the potato slices in the dish. Layer with half of the spinach, half of the onion and half of the tuna sauce. Repeat layers, finishing with tuna sauce. Cover with foil and bake for 30 minutes.
- Remove the foil and sprinkle with extra Parmesan. Bake for a further 15-20 minutes, uncovered until potato is tender and the top is golden.
Tip: Buy a wedge of Parmesan rather than packets of ready grated or shaved Parmesan. It has a better flavour, is cheaper, and will keep for 1 month when wrapped and sealed in a snap-lock bag in the fridge.