Trim any excess fat from the beef and chop it into small pieces.
Dice the onion and mash the anchovies into a paste.
In a heavy-based saucepan, combine the beef, onion, anchovy paste, water, salt, cayenne, nutmeg, allspice, and butter.
Bring to a boil, then reduce the heat to a very gentle simmer. Cover and cook for about 3 hours, stirring occasionally. Add a little more water or butter during cooking if needed.
Once tender, let the mixture cool for 15 minutes.
Use a wooden spoon (or fork) to mash the mixture until well combined. You’re not after a smooth purée — just a well-mixed, soft texture.
Taste and adjust seasoning if needed.
Spoon into small glass or ceramic pots, smoothing the tops.
Pour a layer of melted ghee or butter over the top to seal.
Refrigerate until set — ideally at least 4 hours or overnight.
Serve on warm, buttered toast or crusty bread. Also makes a lovely savoury appetiser.