Peel the potatoes, onions, and garlic cloves, and cut everything into medium-sized pieces. They don’t need to be perfect since the soup will be blended at the end.
Wash the Portuguese kale thoroughly under running water. Remove the thicker stems, roll the leaves, and cut them into very thin julienne strips.
In a pot, combine the cold water, onion, garlic, potatoes, and salpicão (or chouriço). Bring to a boil.
Once it starts boiling, reduce the heat, season with salt (sparingly, since the salpicão is already salty), and let the vegetables cook.
When the potatoes are fully cooked, turn off the heat. Remove the salpicão onto a plate and blend the soup with an immersion blender until smooth.
Turn the heat back to medium, add the julienned kale, and cook until tender.
Meanwhile, remove the casing from the salpicão and cut it into small slices.
When the kale is cooked, turn off the heat, add the sliced salpicão to the soup, and drizzle generously with olive oil.
Adjust the seasoning before serving.