Potato lasagne

Ingredients:
- 1 white onion
- 2 cloves of garlic
- 5 tbsp of oil
- 500g of minced beef
- 2 tbsp of tomato purée
- 800g of peeled tinned tomatoes
- 1 tsp of chopped oregano
- 1 bunch of parsley
- 2 to 3 tbsp of lemon juice
- 800g of firm fleshed potatoes
- 600g of courgettes
- 200g of feta cheese
- 50g of butter
- 40g of flour
- 50cl of milk
- Grated nutmeg
- Salt
- Black pepper
Preparation:
1. Peel the onion and garlic, chop and brown them in 1 tbsp of olive oil, add the minced meat and cook over and medium heat, stirring continuously for 5mins.
2. Add the tomato purée, the peeled tomatoes and the oregano, leave to cook gently for 20mins.
3. Wash, dry and finely chop the parsley, add to the meat, season with salt and pepper and pour over the lemon juice.
4. In the meantime, peel, wash and cut the potatoes into thin slices, wash and thinly slice the courgettes, put them separately into two oven proof dishes and drizzle over 2 tbsp of olive oil.
5. Place them in a preheated oven, on the hottest setting, brown the courgettes for 5mins and the potatoes for 8mins.
6. Continue cooking the courgettes and the potatoes for 25 to 30mins at 200°c (gas mark 7).
7. Butter a gratin dish, arrange a third of the potatoes in the bottom, half the meat and half the courgettes, crumble 50g of feta over it, season with salt and pepper.
8. Add the second third of potatoes, the remaining meat and courgettes, and sprinkle again with 50g of crumbled feta, add salt and pepper.
9. Finish with a final layer of potatoes, add salt and pepper.
10. Melt the butter, sprinkle with flour and mix together gently, then pour in the milk little by little beating continuously.
11. Bring to the boil and leave the mixture to simmer, uncovered, over a low heat for 5mins, dice the rest of the feta into small pieces and incorporate into the béchamel sauce, season with salt and pepper and add the grated nutmeg.
12. Pour the sauce over the potatoes, and cook the gratin in a preheated oven at 180°c (gas mark 6) for 1 hour.
Preparation time: 25mins
Cooking time: 2hrs 15mins