In a large soup pot, heat the olive oil over medium heat and add the onion, leek, carrot, fennel and celery. Cover, lower heat and sweat the vegetables in the olive oil for about 10 minutes, or until soft and glistening. Stir in the garlic, then add the cubed winter squash and toss to coat in the olive oil.
Add the two paprika, cumin and turmeric, stir and cook for a minute or two, for the spices to bloom.
Add enough water or stock to come about two inches/ 5 cm above the vegetables. Cover and simmer until the vegetables are soft, checking on the liquid level and replenishing si that there is always about an inch/2 cm of liquid topping off the solids. The vegetables will take about 45 minutes to cook.
Remove from heat and puree the hot soup with an immersion blender until smooth and velvety. Return to stovetop and add three inches of water. Bring to a simmer and add the trahana. Simmer until the trahana is very tender, about 20 minutes, adding more liquid as needed to keep the soup consistency thick like porridge. Season to taste with salt, stir in the lemon zest and lemon juice.
To serve, ladle into bowls and shave Greek graviera cheese or any mild, nutty sheep’s milk cheese on top then drizzle with extra virgin Greek olive oil. You can also top this with crumbled Greek feta, equally delicious!