Brazilian chocolate truffles (Brigadeiros)

1. Put the sweetened condensed milk, cocoa powder and most of the butter (keep a little back for shaping) in a heavy-based non-stick pan.

2. Stir constantly over a medium-low heat with a silicone spatula so it doesn't catch.

3. After 10-12 minutes the mixture thickens: it's ready when tilting the pan makes it come away from the side in one mass and the spatula leaves a trail on the bottom for a moment.

4. Turn out onto a buttered plate, cool at room temperature, then chill for 30 minutes.

5. With buttered hands, roll into walnut-sized balls and coat each in chocolate sprinkles.

6. Serve in small paper cases.

Tip: No Brazilian birthday is complete without brigadeiros – they're named after Brigadier Eduardo Gomes in the 1940s; if yours are too soft, cook the mixture a minute or two longer, as the texture comes down to cooking time.