Pre-heat the oven to 180°C/350°F Use oil to grease a muffin pan or line it with paper cups.

Chop the Dark Cooking Chocolate in small pieces. Place the Butter and Dark Cooking Chocolate in a heatproof bowl. Melt the Dark Cooking Chocolate in a double boiler (1). Allow to cool.

Optional: Add the Instant Coffee Powder to the melted chocolate while it is still warm, and stir (2).

Mix the eggs and caster sugar in a bowl with a mixer for 5 minutes or until they are pale and have doubled their volume.

Reduce the speed to low and add the melted Chocolate/Butter and Vanilla Extract. Mix for a few seconds until well combined.

Mix in the Cacao Powder and Flour (3). Mix until well combined. Do not overwork the batter

To make Chocolate Chunks, chop the remaining Dark Chocolate and then fold it into the muffin batter.

Bake the batter for about 10-12 minutes in a Muffin Pan. Let cool completely before removing the muffin pan from the oven.