1. Rinse and wash leeks. The best method I have find is to cut the green parts just above when the bright lime and white leek color starts. Cut the top hairs of the leeks and slice in half length wise. Rinse under running water holding from white tops to greenish ends. This will
prevent the sand and dirt getting into the white parts. Make sure you use a clean board to slice the leeks after washing them. Sand particles are very sneaky and they can ruin your soup, be alert. On a separate note, Save deep green parts, wash them, and cut into 3" pieces, you can make a marvelous stock for feature soups.
2. Over medium heat, warm up a medium large pot, melt butter and oil, add leeks a pinch of salt and 4 tablespoons of chicken stock. Toss well, cover pot with a lid, lower the heat and let them sweat for about 4-5 minutes.
3. When the leeks start softening, and still bright green, reserve about 4 tablespoons in a little ramekin set aside.
4.Add diced potatoes, chicken stock, black pepper and salt, bring it to a high simmer, cover pot and reduce heat. Cook for about 8 minutes or until potatoes are soft but still retain their shape.
5.Once potatoes are cooked to your desired consistency, add dill, and heavy cream. Stir, and lower the temperature about medium low. with the help of an immersion blender just pulse 2-3 times into the soup to add some creaminess. I leave about 1/2 of the potato diced and half pureed. If you do not have an immersion blender, grab a potato masher, or puree 1 cup of the soup in the blender, until smooth, then add to the soup and stir until well incorporated. At last add the poblanos, cut into strips or diced, and save some to garnish the soup when served. Let the soup warm up, do not let it boil. Serve with a dollop of Greek yogurt and extra slices of charred poblanos. Enjoy!