Cut the onion in half and slice into 1 cm wedges (bigger slices are best). You don't have to do anything with the beef.
Put all the ingredients in a pressure cooker and turn on the heat.
When the weight starts to move, reduce the heat to medium and cook for 3 minutes. Turn the heat off.
Open the lid after the pressure is released. Add grated ginger if you prefer (about 2 cm from the tube). Done!
Story Behind this Recipe
My child is getting old for baby food, but I always keep forgetting to set a portion aside for him. I don't want to be bothered to make another dish for him either. I started cooking with a pressure cooker to simplify cooking. This dish is healthy as it's not fried and the meat is tender. Prepare steamed rice and a filling miso soup as you wait.
If using cheap meat, season the beef with sake to tenderize and remove the odor. I seasoned the dish lightly and the meat is tender enough to handle with chopsticks. You can serve this to little children as it is. Separate your children's portion before adding the ginger.