1 lb. collard greens or 1 large bunch, washed
1/8 cup extra-virgin olive oil
1/2 lb. Portuguese linguiça or Spanish chorizo sausage, sliced in half lengthwise
1 medium sweet onion, diced
6 garlic cloves, sliced
2 tsp. kosher salt
2 large Russet potatoes, peeled and diced
4 cups low-sodium chicken stock
Pepper vinegar, to taste
Remove the stems from the collards. (Reserve for collard stems barigoules.) Lay out the leaves in stacks of several leaves each. Roll the stacks into cylinders and cut the cylinders into very thin slices.
Heat the olive oil in a large soup pot or Dutch oven over medium-high heat. Add the sausage cut-side down and sear it for two minutes. Add the onions, stir, and cook them until they are soft and translucent, about seven minutes. Add the garlic and cook, stirring, for two to three minutes, or until soft. Add the salt, potatoes, and stock. Bring to a simmer and cook until the potatoes are tender, about 20 minutes. Remove the sausage and let set until it is cool to the touch. Remove and discard any casing, crumble the sausage, and reserve.
Move the potatoes over to one side of the pot and, using a potato masher or the back of a spoon, lightly mash the potatoes. Stir. (It doesn’t matter if a small amount of onions and garlic is mashed, too.) Reduce the heat to medium-low. Add the crumbled sausage and the collards and simmer for six to eight minutes, or until the collards are tender but still crisp. Add pepper vinegar as desired.