Strain, cool until safe to handle, and squeeze out the leeks to remove all the moister.
Using a sharp knife, chop the leeks thinly.
Combine the cooked leeks, potato, and breadcrumbs in a large bowl. Using a fork mash the cooked potato.
Add the egg, chopped herbs, garlic, turmeric, salt, and pepper. Add Feta (optional). If the mixture is too soft to form patties, add a little more breadcrumbs.
Preheat the oven to 400°F/200°C and line a baking sheet with parchment paper.
Spray or brush the baking sheet with oil.
Using your hands, shape the mixture into patties.
Place the patties on the prepared baking sheet and spray or brush the tops.
Bake until golden, about 20 minutes, flipping halfway through. Serve immediately or at room temperature.