- Preheat the oven to 180°C.
- Place the Fish Fingers on a baking tray and bake until crispy and golden.
- Meanwhile heat half the butter in a saucepan until foaming. Add the carrots and cook for around 5 minutes, then add the leeks and continue cooking until soft.
- Add the rest of the butter and flour and cook out for a minute or so until smelling biscuit.
- Pour in the milk gradually, beating it in with a wooden spoon, until you have a thick sauce. Bring to a simmer and cook for a few minutes then add most of the parmesan.
- Use a little oil to grease a medium sized baking dish and add a layer of the sauce. Place the first layer of lasagne sheets on top.
- Top with another layer of the sauce, half the fish fingers, spinach, peas. Top with lasagne sheets and repeat again, topping with a final layer of lasagne sheets, sauce and sprinkling of parmesan.
- Bake for around 30 minutes until golden and bubbling.