1. To prepare the filling, peel the onion and garlic and chop finely. Cut the leek into rings and wash thoroughly – there is often sand between the layers. Clean, wash and drain the spinach. Set everything aside.

2. Heat up a large pot with some olive oil. Add the chopped onion and sauté until soft and glossy. Add the leek rings and garlic and cook until soft and glossy as well. Next, add the minced meat and cook until the meat is nicely browned. Add the spinach, mix in, and cook everything for 5-6 minutes until the spinach has wilted down and almost all of the liquid in the pot is gone. Remove from the heat and let cool down for about 10 minutes, then add the crumbled feta and season well with salt, pepper, and some chili flakes if you like it hot (optional).

3. Preheat the oven to 350°F (180°C). Line a baking sheet with baking parchment and set aside. Place a sheet of filo dough on your work surface and brush with some oil (not too much). Place another sheet on top and press together. Cut into three strips and place a bit more than a tablespoon of filling on one end of a strip and fold over itself several times to create triangle packages. Brush the end of the filo dough strip with some more oil and close the package. Place on the prepared baking sheet and repeat with the remaining filo dough and filling – you should get around 12 packages. Brush the triangles with a little more olive oil and sprinkle with sesame seeds. Bake for 32-36 minutes or until browned and crisp to your liking. Take out of the oven, transfer to a wire rack, and let cool down. Serve still a bit warm or cold.