Preheat the oven to 230 C or 450 F.

Generously butter 4 ramekins or small bowls and dust with cocoa powder or all-purpose flour, tapping out any excess cocoa or flour.

In a microwave safe bowl, add the chocolate and butter. Microwave stirring every 30 seconds for about 2 minutes or until smooth. Then set aside. You can also do this step over a double boiler.

Beat the eggs, vanilla and sugar using a whisk or electric mixer until the mixture has doubled in volume. It should be pale and fluffy. This takes about 5 minutes.

Fold in the chocolate-butter mixture and all-purpose flour until well-combined.

Divide the mixture among the 4 ramekins. At this stage, you can cover them with clingfilm and chill for several hours before baking, or you can bake them immediately.

Bake the lava cakes for 7 minutes. They should have puffed up slightly and should jiggle when shaken.

Let the cakes cool for 1-2 minutes, then serve immediately.

To serve, run a knife through the edges of the ramekin and invert onto a plate.

Dust with sugar or cocoa and serve with berries, ice cream or whipped cream.