Preheat the oven to 180°C/160°C fan/gas mark 4.

Line a Le Creuset 24cm Square Cake Tin with baking paper and spray with cooking spray.

Prepare the plums by cutting them in half and removing the pits. Slice in half and into thin, even slices. Sprinkle 1 tablespoon of sugar on the base of the lined tin, layer the plum slices in straight lines, slightly overlapping until the surface is completely covered. Sprinkle the remaining 1 tablespoon of sugar over the plums.

To make the cake batter, beat the eggs, sugar, and vanilla until pale and thick. In a medium-sized bowl, melt the butter and chocolate in the microwave in short bursts, stirring at every interval to ensure the chocolate does not burn.

Sift the flour and baking powder. Fold the dry ingredients into the sugar and eggs mixture to combine. Slowly add the melted butter and chocolate, followed by the milk and thyme. Mix until just combined.

Pour the mixture into the tin and bake for 50-60 minutes until golden and cooked through. Cover at the 40-minute mark with tin foil to prevent the top from browning too much.

Remove from the oven and cool on a Le Creuset cooling rack with the cake still in the tin. Once cooled, turn out and serve warm with double cream yoghurt.