Wash and slice the 5 leekss and the 4 fresh spring onionsand the ½ cup dill. Wash and chop the 1 kilo fresh spinach. Set the dill aside for later.
Preheat oven to 180℃.
In a large pot, sauté the finely chopped 5 leeks 4 fresh spring onions over medium heat for 5–6 minutes, until they become translucent.
Toss in the chopped fresh spinach and continue sautéing with the ¼ cup olive oil.
In the meantime, prepare the tomato sauce. In a medium-sized pot, add the 2 cups tomato sauce, 1 ½ tbsp oregano, 1 tbsp sugar, pepper, salt, 1 tsp smoked paprika, and 1 garlic clove . Simmer for 15 minutes on medium heat.
Remove the spinach mixture from the heat. Let it cool for a bit before adding the 2 cups feta cheese. Give it a gentle toss.
Remove the tomato sauce from the heat. Using a ladle, spread a layer of the sauce over the bottom of the baking pan before you begin layering the lasagna.
Use the 15 lasagna noodles and start to layer the lasagna noodles over the sauce, then spread a generous layer of the spinach mixture on top. Sprinkle with shredded mozzarella, followed by a ladle of tomato sauce. Repeat the process, alternating noodles, spinach filling, cheese, and sauce, until you’ve used all the lasagna sheets.
Pour the remaining tomato sauce over the top of the lasagna, then finish with the 1 cup shredded mozzarella .
Bake for 40 minutes until the lasagna noodles are tender.
Remove from the oven and let it cool off before cutting into the lasagna.