Prepare your ramekins. Generously butter the insides of four 180ml ramekins, making sure you get into every corner. Dust each one with cocoa powder, tapping out any excess. This step ensures your cakes will release cleanly—you'll see a lovely, even coating of cocoa against the butter.

Melt the chocolate and butter together. Place the chopped chocolate and butter in a heatproof bowl set over a pan of gently simmering water. Do not let the bottom of the bowl touch the water. Stir occasionally with a silicone spatula until the mixture is smooth, glossy, and completely melted—you'll smell that deep, almost smoky chocolate aroma as it comes together. Remove from the heat and set aside to cool for five minutes.

Whisk the eggs and sugar. In a large mixing bowl, combine the whole eggs, egg yolks, and golden caster sugar. Using a hand mixer or a stand mixer fitted with the whisk attachment, beat on high speed for about 3-4 minutes. You're looking for the mixture to become thick, pale, and ribbony—when you lift the whisk, the batter should fall back into the bowl in a slow, lazy ribbon that holds its shape for a second before disappearing.

Fold the chocolate mixture in. Pour the cooled chocolate-butter mixture into the egg mixture, along with the vanilla extract and a pinch of salt. Using a large metal spoon or a rubber spatula, fold gently but firmly. Cut through the centre of the mixture, then scoop around the edge of the bowl, repeating until just combined. You should see a uniform, dark brown batter with no streaks of egg—stop folding the moment it comes together; overworking will make the cakes dense.

Sift and fold the flour. Sift the plain flour over the batter. Fold again with the same gentle motion until the flour disappears into the mixture. The batter will be thick, glossy, and smell intensely of chocolate. If you're adding an extra chocolate square for a more dramatic lava, gently press one square into the centre of the batter in each ramekin at this point.

Fill and rest. Divide the batter evenly among the four prepared ramekins. You can do this up to 24 hours ahead—cover them with cling film and refrigerate. If baking immediately, let the filled ramekins rest at room temperature for 10 minutes. This resting time allows the batter to settle and ensures a more even bake.

Bake with precision. Preheat your oven to 200°C (180°C fan) and place a baking tray inside to heat up. Place the ramekins on the hot tray and bake for exactly 12-14 minutes. You'll know they're ready when the tops are set and slightly domed, the edges look firm and have pulled away just a little from the ramekin sides, and the centre jiggles ever so slightly when you gently shake the tray. The surface should feel springy to a light touch, but the middle will still be soft beneath.

Rest and unmould. Remove the ramekins from the oven and let them rest on a wire cooling rack for exactly one minute—no longer, or the lava will set. Run a small, sharp knife around the edge of each cake to loosen it. Place a serving plate upside down over the ramekin, then confidently invert the plate and ramekin together. Lift the ramekin away to reveal a perfectly shaped cake. My kids absolutely devour this every time I make it, so I always have a plate ready and waiting.