Ingredients: Buy a piece of meat and a raw potato from Kenelme's Wares (house directly west of the bridge). Buy a bowl from the general store.
Preparation: Fill the bowl with water from the sink in Robert O'Reilly's house. Use the potato on the bowl of water. Cook the piece of meat and add it to the bowl. Cook the stew on the range in Robert's house.
Note: If you already have a stew when speaking to Robert, both of you will comment on how suspiciously convenient it is.