Wash and trim the green beans. Line up a handful of beans and cut off the tips in one slice. Only remove the tougher ends, those that were attached to the stem. You don't have to remove the top side with the tender shoots. Halve the beans if very long.
Bring a pot of water to a boil. Add salt generously and 1 teaspoon butter. Cook the green beans until tender but still crisp, about 6 - 7 minutes or to your liking.
While the green beans are cooking, fill a large bowl with water and add ice cubes and set it aside.
Drain the beans in a colander and plunge them into the ice water immediately. This way they will retain their bright green color and remain crisp.
Drain the green beans again and pat dry with kitchen paper.
Melt 3 tablespoons butter in a large pan. Add almonds and cook on medium heat, stirring often, until golden brown, about 3 minutes.
Add the green beans, half of the lemon juice, salt, and freshly ground black pepper. Stir well to coat the green beans with butter. Reheat for about 1 minute, they should become glossy.
Add more lemon juice, salt, and pepper to taste. Sprinkle some chopped parsley on top.