Preheat your oven to 200°C (180°C fan). Generously butter four 200ml ramekins and dust them lightly with a teaspoon of cocoa powder. The smell of warm butter will fill your kitchen as you work.

Whisk the dry ingredients. In a large bowl, combine the coconut flour, cocoa powder, erythritol, baking powder, salt, and cream of tartar if using. The mixture should look like fine, dark sand with no lumps — run your fingers through it to check.

Blend the wet ingredients. In a separate jug, whisk the eggs until they are pale and frothy, about 1 minute. Stir in the almond milk, melted butter, and vanilla extract until the liquid is a uniform, glossy brown.

Combine wet and dry. Pour the wet mixture into the dry ingredients and stir gently with a spatula. The batter will thicken quickly as the coconut flour absorbs the liquid — it should resemble a thick, scoopable brownie batter that smells deeply of chocolate and vanilla.

Add the chocolate chunks. Fold in the chopped dark chocolate. Reserve 4 small pieces (about the size of a hazelnut) to place directly in the centre of each ramekin later. The batter will now have visible flecks of chocolate that will melt into lava.

Fill the ramekins. Divide the batter evenly among the four ramekins, smoothing the tops with the back of a spoon. Press one reserved chocolate piece into the exact centre of each cake, pushing it down gently until it's just covered by batter.

Bake immediately or refrigerate. Place the ramekins on a baking tray and bake for 12-14 minutes. At 12 minutes, the edges should look set and slightly pulling away from the sides, while the centre jiggles softly when you gently shake the tray. The top will be matte, not shiny, and a toothpick inserted 1cm from the edge should come out clean.

Rest for exactly 1 minute. Remove from the oven and let the cakes sit on the counter for one minute — no longer. Run a thin knife around the inside edge of each ramekin, then invert onto a small plate. The cake should release with a gentle thud, revealing a dark, glossy top. Cut into it immediately to see the molten centre flow.