To make the syrup dissolve the sugar with in the water over a low heat. Once dissolved, turn the heat up to medium and boil until the syrup turns a pale amber colour.

Grease a 20cm glass flan dish while the syrup is cooking and then cut the plums in half removing the stone.

Place the plum halves cut side down in the dish.

Once the syrup is ready pour it over the plums and set to one side.

To make the base of the tarte cream the butter and sugar together (ideally with an electric whisk) until pale and fluffy.

Add the egg, flax seeds, sour cream and lemon zest, mixing together again before finally adding the almonds, flour and baking powder and giving it a final mix.

Place the mixture on top of the plums and spread evenly.

Bake in a pre-heated oven at 180 degrees, 160 degrees fan oven for approx. 30 minutes until golden and firm to the touch.

Cool for 5 minutes before turning out onto a serving plate.

Serve either warm or cold.