Preheat and prepare: Set your oven to 200°C (fan-assisted 180°C). Generously butter two 175ml ramekins, making sure you get into all the nooks. Dust them lightly with a little extra cocoa powder, tapping out the excess. The aroma of warm butter and cocoa is your first clue that something special is underway.

Melt the chocolate and butter: Place the chopped chocolate and butter in a heatproof bowl set over a pan of simmering water (don't let the bowl touch the water). Stir gently until smooth and glossy — you'll see the mixture turn into a dark, silky river. Remove from the heat and let it cool for a couple of minutes.

Whisk the eggs and sweetener: In a separate bowl, whisk the eggs, erythritol, and vanilla extract together until pale, thick, and frothy. This should take about 2–3 minutes by hand, or 1 minute with an electric mixer. You're looking for a pale, airy mixture that has almost doubled in volume and smells sweetly of vanilla.

Combine wet ingredients: Gently fold the cooled chocolate mixture into the egg mixture. Use a spatula and a light hand — you want to keep as much air in the batter as possible. The batter will be a deep, glossy brown, and the smell of rich chocolate will fill your kitchen.

Add the dry ingredients: Sift the coconut flour, cocoa powder, baking powder, and salt over the batter. Fold again, just until no streaks of flour remain. The batter will thicken slightly as the coconut flour absorbs moisture, becoming a spoonable, fudgy consistency. You'll feel it change under the spatula.

Assemble the lava centre: Spoon half the batter into the prepared ramekins. Make a small well in the centre of each with the back of a spoon. Drop 1 tablespoon of double cream into each well, then cover with the remaining batter, smoothing the tops gently. The cream will create that glorious molten surprise.

Bake with precision: Place the ramekins on a baking tray and bake for exactly 12–14 minutes. The edges should look set and slightly puffed, while the centre should still jiggle ever so slightly when you gently shake the tray. The surface will have a papery, cracked look — this is exactly what you want. The smell at this point is intoxicating.

Rest and serve: Let the cakes cool in the ramekins for 45–60 seconds — no longer. Run a thin knife around the edge of each ramekin, place a plate on top, and flip it over. Give it a gentle tap, then lift the ramekin. The cake should slip out, revealing a perfectly domed top. Serve immediately, while the centre is still warm and flowing.