Caldo verde, a potato and kale soup from northern Portugal, is one of those dishes that seem custom-made for lazy rainy days, when you want something hearty and comforting but don't feel like putting in a ton of effort. It's made with a few cheap and simple ingredients, it takes all of maybe 10 minutes of prep work, and it's ready to eat just half an hour later. Oh, and it's all made in a single pot, too. And did I mention delicious? It's delicious.
The only way you could really make this any easier is if you could convince someone to make it for you. Even that might take more effort.
Recipes for caldo verde don't vary too greatly. Most start with sautéing some form of allium (onions, leeks, garlic, or a mix) in olive oil, then adding kale, potatoes, and broth and letting it simmer. The only real differences come in the treatment of the kale and the degree to which the whole thing is cooked down. The best caldo verde I had in Portugal was cooked long enough that the potatoes almost completely broke down, thickening the soup into a creamy broth that was tinted deep green by finely shredded strips of kale. (Caldo verde means "green soup," so if you aren't cooking your kale long enough to turn the soup green, you ain't making caldo verde!)
At the same time, I also like the idea of having a few heartier chunks of potato in the soup. It reminds me a lot of ajiaco, a Colombian potato soup made by boiling a few types of potatoes together. The starchier potatoes break down and thicken the soup, while the waxier varieties become tender but hold their shape better. I decided to use the same technique in my caldo verde.
It worked like a charm. After 25 minutes of simmering, russet potatoes become tender enough that some rough stirring causes them to shed starch and thicken the soup. Meanwhile, Yukon Golds hold their shape nicely. Twenty-five minutes is also plenty of time for even tough curly kale to soften up.
The soup can be made entirely vegetarian by using either vegetable stock or water as the base, but chicken stock will give it a bit more flavor if you don't mind the meatiness. Adding some form of sausage to the soup is also not a necessity, but it's not uncommon. Sausages like chouriço, linguiça, or salpicão—a hard pork sausage flavored with red wine and paprika—are typically cooked separately, then added to the finished soup as a garnish. Most places I've shopped at in the US that have these sausages available sell them precooked, which makes them very convenient for soups like this. Just slice them up and add them toward the end of the simmering.
Really traditional Portuguese-style sausages can be a little tough to find in the US, but any garlicky precooked or dry-cured pork sausage can stand in. Go with what's available and what you like.
I just realized that there's something universally comforting about that combination of potato, brassica, and sausage in a soup. You can see how this caldo verde is kissing cousins with Polish kapusniak, for instance, despite being from the opposite side of the continent. (I'm not exactly sure where my mom's hot dog, potato, and cabbage soup fits into that family tree, but it's a family I'd like to get to know better.)