- 1 large onion, chopped
- 2 peppers, chopped (I used 1 yellow and 1 green)
- 1 tin of chopped tomatoes
- oregano (or whatever herbs take your fancy)
- 1.5 aubergines (or just use 2), sliced
- 3 potatoes, peeled and thickly sliced
- 2 tbsp butter
- 2 tbsp flour
- Half litre of milk
- Ball of mozzarella, chopped
Saute the onions in some olive oil, add the peppers and cook for a couple of mins, then the herbs and tomatoes. Season and leave to simmer gently while you prepare the rest. Peel and slice the potatoes and parboil for 5 mins. With root vegetables you should boil from cold rather than blanching (already boiling water) as they are denser.
A science bit: Alway, always use salted water as this increases the boiling point (boiling point elevation, a colligative property) meaning the water is hotter.A liquid cannot be hotter than its boiling point (unless it's superheated but that's a story for another day) and hotter liquid means faster heat transfer and more of it and therefore faster cooking. While we're on the subject the boiling point is when a liquid's vapour pressure is equal to the atmospheric (external pressure) and is seen to occur when evaporation occurs throughout the liquid.
Anyway back to the recipe: After cooking the potatoes the water will be nice and hot so blanch the aubergines for 3 mins.
Some old recipes will tell you to salt the aubergine, let it sit then rinse off the salt (a browny liquid will be present on the surface). This serves 2 purposes, it reduces the amount of oil absorbed during cooking but it mainly serves to reduce the bitterness (this is tempered by cooking anyway). Modern varieties eaten in Europe have had this bitterness bred out of them so this in no longer necessary (unless you really want to reduce the amount of oil absorbed).
Now to make the Béchamel: Melt the butter in a pan, add the flour and cook gently for a couple of mins to make a white roux. Whisk in the milk a little at a time and bring to the boil. Keep whisking as you heat coz the sauce will try to stick to the bottom of the saucepan. Once it has reached boiling point simmer for about 10 mins (don't forget about its sticking tendencies). Stir in the mozzarella. Technically this is now called a Mornay sauce.
I layered like so: Potatoes, tomato sauce, aubergines, potatoes and then the Mornay sauce. Baked at 180 for 25 mins. Check it to ensure the potatoes in particular are cooked through.
If you want to make this with meat you should basically make a pasta sauce in place of the tomato sauce. You can fry the aubergines instead of boiling and the potatoes as well but I don't like dealing with hot oil and avoid it whenever possible.