Wash the wild leafy greens thoroughly and drain.
Into a large saucepan pour the olive oil, add the onions and leeks and sauté for 3-4 minutes, until wilted.
Add the wild greens and mix with a wooden spoon. As soon as they become wilted, lower the heat and add 1/2 cup of water.
With the lid on, simmer for 35 minutes, until the wild greens are boiled.
In the meantime, prepare the feta sauce. Into a blender add the feta cheese (crushed).
In a small pot, warm the milk and the milk cream at low heat. Right before it comes to the boil, remove from the stove and let it cool for 1 minute.
Pour the milk in the blender, along with the herbs and spices and blend, until the sauce becomes smooth.
Serve the horta at room temperature and drizzle some extra virgin olive oil and lemon juice. Top with the feta sauce and some grated tomato, if you wish.