DIRECTIONS:

Thinly slice the potato (approx. 4-5 mm)
Chop the bacon and stir-fry it without using oil.
Grease a baking tin with butter. Spread a layer of potato (don’t forget to sprinkle salt and pepper). Spread a thin layer of tuna (without oil), another layer of potato and another of bacon. Alternate the tuna and the bacon until filling up the tin.
The last layer must be potato, pour the bechamel over the pie (approx. ½ lt).
Bake for 30-40 minutes at the highest temperature. The cooking time depends on your oven and the potato and pie thickness. It’s important you check if it’s cooked using a fork.
Once done, add cheese (grated, sliced or as preferred), sprinkle the oregan and bake au gratin.
You can use packaged bechamel or make it at home by putting on an non-stick pan two full tablespoons of oil and flour. Stir-fry and add ½ lt of milk (at room temperature), salt, pepper and nutmeg (optional). Cook at medium heat until desired thickness.
Remember that bechamel gets thicker when it cools down.