Step 1

Place beans in a large bowl; cover with cold water. Stand overnight. Drain well.

Step 2

Cook beans and garlic in a large saucepan of boiling water for 1½ hours or until very tender. Drain well.

Step 3

Blend or process beans, garlic, juice and the water until smooth. Season with pepper to taste. Transfer to a small bowl, cover to keep warm.

Step 4

Meanwhile, make chimichurri, combine ingredients in a small bowl; mix well. Season with pepper to taste.

Step 5

Slice beef; serve with bean puree, chimichurri and combined watercress and onion.