Resting the fondants for 5 minutes allows the outside to finish setting while keeping the centre beautifully soft.

The batter can be piped into the prepared moulds and frozen for up to 3 months. Bake directly from frozen, adding approximately 5 minutes to the cooking time.

Keep the baking paper no more than 1cm above the mould, as the fondants rise during baking and require room to expand.

Melting the chocolate: on induction you can hold a very low, steady heat, so melt the chocolate and butter directly in the pan without a double boiler. On a gas flame the direct heat is much harsher, so use a double boiler there, as that's where chocolate most easily scorches and turns grainy.

If the chocolate starts to tighten or turn grainy, take it off the heat straight away and stop stirring for a moment. If it has only just started, it can often be brought back by stirring gently off the heat until smooth. Don't add more heat to fix it, as that makes it worse. If it has gone fully hard and dull, it has burnt and needs to be started again.

This recipe makes 15 fondants. To make 6, use 40% of every ingredient: 144 g dark chocolate, 100 g butter, 56 g flour, 100 g sugar and 4 eggs. The method stays the same, and the baking time depends on the size of the moulds rather than how many you bake at once.

Bake on Fan Plus at 170°C, shelf position 2, for about 12 minutes. They're ready when the edges are just set and the top is still moist and shiny in the centre. Rest them for about 5 minutes before turning out: they keep cooking gently from the residual heat, which firms the outside enough to hold its shape while the centre stays molten.

Fondants can be made ahead: fill the metal rings, freeze, and store airtight for up to 3 months. To bake, leave them at room temperature for about 5 minutes, then bake from frozen, adding roughly 5 minutes to the normal baking time.

Fan Plus is used rather than conventional heat because the fan circulates heat evenly all around each mould, so every fondant sets at the same rate on the outside while the centre stays molten. With conventional heat, the fondants nearer the elements cook faster and the batch can come out uneven.

The times here are for the metal rings used in the video. A larger or deeper mould takes longer to set, and a smaller one is quicker. Don't rely on the clock alone: check early and judge by the signs above, which are set edges, a moist, shiny centre and a slight wobble.

If the chocolate starts to tighten or turn grainy, take it off the heat straight away and stop stirring for a moment. If it has only just started, it can often be brought back by stirring gently off the heat until smooth. Don't add more heat to fix it, as that makes it worse. If it has gone fully hard and dull, it has burnt and needs to be started again.