Clean the leeks and chop off the rough dark green ends. Leave a lot of green. Slice into thin rounds.
Melt butter alternative over medium heat. Add leeks and cook down until soft. Add the chopped onions. Cook until the onions are starting to go translucent. The leeks will be just starting to brown. Add the hard cider and turn temperature to a simmer.
Add potatoes, broth, a little freshly ground black pepper, thyme, soy sauce, and green chile sauce. Simmer until potatoes can be mashed with a wooden spoon.
Remove from heat, and whir up with an immersion blender until creamy. Add salt and pepper to taste. If you're #notvegan, serve with some grated Havarti on top.
Notes
This potato soup uses zero dairy, but if you're just going vegetarian and you're not vegan, add a little Havarti right before serving.