Preheat the oven to 180°C. Season the beef with salt and pepper, add about 2 tablespoons of oil and mix well. Heat a large frypan over a medium-high heat. Brown the beef in 2 or 3 batches. Remove each batch and place in a casserole dish.
Reduce heat in pan and add a little oil. Add the onion, garlic and capsicums, cook for 1 - 2 minutes and stir occasionally.
Sprinkle in the flour and stir until the vegetables are coated. Gradually pour in the stock, stirring well. Add the tomato paste and oregano. Pour over the beef in the casserole dish and stir to combine. Cover the casserole dish, place in the oven and cook until the beef is very tender. In the last 30 minutes of cooking time, add the tomatoes and cannellini beans.