Step 1

Place olive oil in large pot or Dutch oven over medium heat. Add onions and garlic and a pinch of salt and ground black pepper. Saute until onions are translucent.

Step 2

Add the diced potatoes to the pot and saute for a minute. Then add three cups of mushroom stock along with sage and bay leaves. Add red pepper flakes, if using.

Step 3

Bring the stock to a boil, cover, and cook until the potatoes are tender, about 8-10 minutes.

Step 4

Use an immersion blender to blend the soup (don't make it too smooth, you want chunks of potato in there). Alternatively, remove half the soup to a blender jar and blend carefully until smooth. Add the blended soup back to the pot.

Step 5

Add the collard greens to the pot and mix them in. You can add in up to two more cups of broth to the soup to thin it out to your liking.

Step 6

Stir in the soy sauce, if using followed by the kidney beans. Mix well, bring to a boil, cover and let the caldo verde simmer for five more minutes or until the collards are very tender. Check salt and add more as needed. Serve hot.