Preheat and Prepare: First, preheat your oven to 200°C (180°C fan). Thoroughly grease the inside of four 175ml ramekins with butter, making sure to cover the bottom and all sides. Add the cocoa powder and turn the ramekins to coat the inside completely, tipping out any excess. Place the prepared ramekins on a baking tray.

Melt the Chocolate and Butter: In a heatproof bowl set over a saucepan of simmering water (a bain-marie), melt the chopped chocolate and butter together, stirring occasionally until smooth and glossy. You can also do this in the microwave in 20-second bursts, stirring in between. Once melted, set it aside to cool slightly for about 5 minutes.

Whip the Eggs: In a separate large mixing bowl, using an electric hand whisk or a stand mixer, beat the whole eggs, egg yolks, and caster sugar together on a high speed. Continue whisking for about 5-7 minutes, or until the mixture is pale, thick, and has tripled in volume. It should fall from the whisk in a thick ribbon that holds its shape for a moment on the surface.

Combine Wet Ingredients: Add the vanilla extract to the slightly cooled chocolate mixture and stir. Gently pour the chocolate mixture into the whipped eggs. Using a large spatula, carefully fold them together until just combined. Try to be gentle to keep as much air in the eggs as possible.

Fold in the Dry Ingredients: Sift the plain flour and salt over the chocolate-egg mixture. Fold everything together gently until no streaks of flour remain. What works best for me is to stop mixing the moment it's combined to avoid overworking the batter, which can make the cakes dense.

Fill the Ramekins: Carefully divide the batter evenly among the four prepared ramekins. They should be about three-quarters full.

Bake to Perfection: Place the baking tray in the preheated oven and bake for 12-14 minutes. The edges of the cakes will be set and slightly puffed, but the centre will still look soft and have a slight wobble when you gently shake the tray. This wobble is the sign of a perfect molten centre!

Rest and Serve: Carefully remove the tray from the oven. Let the Chocolate Hot Cups rest in their ramekins for just one minute before serving. You can serve them directly in the ramekins or carefully run a knife around the edge and invert them onto a plate. Serve immediately.