Season the beef chunks with salt and pepper.
In a large frying pan (like a heavy stainless steel or cast iron skillet), heat the oil until hot but not smoking. Sear the beef by browning on all sides in the hot oil. Keep some space in between the beef chunks when frying so dont dump all the beef but cook in batches.
Place in a plate as you cook. This method will ensure a deep and delicious taste from the meat so if you can dont omit the step.
In the remaining oil (or add a little oil to the skillet if needed) saute the garlic, onions and tomatoes for 3-4 minutes. The purpose is to deglaze the pan with the juices from the veggies and get all the yummy brown bits remaining there for extra flavor.
Place the beef and the sauteed vegetables in the slow cooker. If theres no time, simply add the browned beef with the vegetables in the slow cooker.
Add the carrots, potatoes and bay leaves. Pour the beef broth (or water), fish sauce or soy sauce and the tomato sauce. Give it a quick stir. Cover and cook on low until the beef is fork tender between 6-8 hours.
When the beef is already tender enough to eat (but not falling apart) add the peanut butter and red bell pepper. You can also add the frozen peas at this point. Add the sugar, if using. This is not to sweeten the stew but to enhance the flavor. Season with extra salt and pepper, if needed. Stir everything gently. Cook for another 30 minutes to 1 hour or until everything is fully heated through.
Serve with freshly steamed rice on the side.
