• We start by putting the eggs in a pot with water to boil. We cook them for about 10 minutes. After that time, cool them under the tap and peel them when they have cooled. Set aside.
• We continue with the sofrito. Chop the onion finely and fry it in a frying pan with a drizzle of oil. As soon as it starts to become transparent, add the tuna, previously drained, the chopped boiled eggs and the tomato. Cook everything together for about five minutes. Set aside.

For the Bechamel sauce

• Put the butter in a frying pan. As soon as it melts, add the flour and let it toast lightly. But be careful not to burn it.

  Add the milk (lukewarm to avoid lumps) and, with a whisk, add the flour and milk, stirring, until you get a homogeneous cream. Cook for a few minutes, until it has the desired texture, and add a pinch of salt, pepper and nutmeg to taste. Set aside.
• Now that we have the filling and the bechamel sauce ready, we only have to assemble the lasagna. In the mold where we are going to bake it, we cover the base with fried tomato. Spread well and cover with the first layer of lasagna sheets. We put filling and repeat the process until we make several layers, as much as the filling will give us.
• Finish with a layer of lasagna sheets, cover with bechamel sauce and put grated cheese on top.

  Bake in a preheated oven at 180ºC for approximately 20-30 minutes, until the cheese is golden brown. And now we have a great tuna lasagna ready.