Heat the olive oil in a large 12-inch skillet over medium heat. Add the onions and leek and cook until the onion is soft and translucent, 6 to 8 minutes.
Turn the heat to medium-low and add the garlic powder, sugar, sweet paprika and salt and pepper to taste. Stir and let cook for about 30 seconds, and then add the crushed tomatoes and tomato paste. Simmer for 15 to 20 minutes until the sauce is thickened. Taste and adjust seasonings.
Add the cherry tomatoes, dill, spearmint and the spinach, a handful at a time, and mix as best as you can. Put the lid on the pan and allow the spinach to wilt. This will only take a few minutes.
Take off the lid and cook for another few minutes on a medium heat until all the moisture has dried up. In this point add feta cheese if using it.
Make four cavities in the tomato mixture. Crack an egg into each cavity, then put the lid on and leave on the heat until the whites are cooked but the yolks are still runny. This should take about 5-8 minutes. Take off the lid and sprinkle over the chili flakes. Serve immediately with fresh crusty bread.
