Caldo Verde (Portuguese Green Soup)

In a large saucepan over medium heat, cook onion and garlic in 3 tablespoons olive oil for 3 minutes.

Stir in potatoes and cook, stirring constantly, 3 minutes more.

Pour in water, bring to a boil, and let boil gently for 20 minutes, until potatoes are mushy.

Meanwhile, in a large skillet over medium-low heat, cook sausage until it has released most of its fat, 10 minutes.

Mash potatoes or purée the potato mixture with a blender or food processor.

Stir the sausage, salt and pepper into the soup and return to medium heat.

Cover and simmer 5 minutes.

Just before serving, stir kale into soup and simmer, 5 minutes, until kale is tender and jade green.

Stir in the remaining tablespoon of olive oil and serve at once.