Fast, simple, and delicious! Lots of different ways to flavour, but I kept it simple to enjoy the flavours of the potato and spinach.
Begin by sautéing the onions in a large pot in the butter or oil. Once translucent and softened, add the potatoes and stock. Bring to a boil, then turn down to a simmer and let cook until potatoes are very tender, about 15 minutes.
Add in spinach, and let cook until tender but still bright, about 1-2 minutes. Blend soup using an immersion blender or in batches in a regular blender. Blend until a smooth consistency is achieved. Add lemon juice, and salt and pepper to taste.
Serve hot with optional garnishes. Enjoy!