Plum Tarte Tatin

100 grams butter
100 grams white sugar
7 large plums halved
1 sheet of flaky or puff pastry (pre-rolled)
The pan you choose for Tarte Tatin is important as it must be able to withstand cooking on a stove top and in the very hot oven with extremely hot caramelizing sugar. A heavy bottomed seasoned cast-iron pan is preferable.
Preheat the oven to gas mark 5. Measure your pan and cut your pastry sheet into a round disc to fit as a lid. Cover the pastry so it doesn't dry out and put aside for later.
Peel the plums and cut into halves removing the stone.
Melt the butter and sugar together in the pan and slowly cook together until the sugar dissolves.
Arrange the plums, skin side down in the sugar mixture in a snug even pattern. Cook over a slow to medium heat for around 10 minutes until the plumbs are slightly soft and the sugar has begun to caramelize.
Place the pastry round securely on top of the plums. Bake in the oven for 15 to 20 minutes until the pastry is golden brown.
Place a serving dish over the pan and flip upside down to release the dessert, so that the pastry is underneath.