Season roast cubes with salt and pepper. Preheat oil in a Dutch oven to medium high; sear cubes, working in batches to avoid crowding the pan. Set browned cubes aside.
Add garlic and onion to the pan, reduce heat to medium low and sear 5 minutes, stirring occasionally. Stir in tomato paste and cook 2 more minutes. Stir in diced tomatoes and beef stock. Bring to a simmer over medium heat.
Return beef cubes to Dutch oven and simmer 1 hour.
Drain farro and add to simmering soup. Cook 15 minutes, add kale and beans; simmer an additional 15 minutes. Add additional salt and pepper to taste. Serve.