Butter, apples and sugar turn into one of the finest desserts in the world.
8 golden delicious apples
125g castor sugar
500g puff pastry e.g. Careme
1 egg, beaten
Creme fraiche, cream or ice-cream for serving
Peel apples and cut in half lengthwise. Use a melon baller to remove core, and trim off any stalks. Melt butter in an ovenproof 25-centimetre frypan and sprinkle with half the sugar. Pack apples in tightly, rounded side down. Cut one or two apples into quarters and squeeze in - they will shrink as they cook.
Scatter with remaining sugar and cook over medium heat, letting them hiss and bubble for about 20 minutes, until there is a lightly golden caramel beneath. Watch out for browning or burning but be brave, you want a real caramel. Press apples down into the pan as they soften. Heat oven to 220C.
Roll out pastry and drape generously over apples, trimming edges so you can tuck it in all round (grease sides with a little butter for easier turning-out). Prick pastry lightly with a fork, brush with beaten egg, and bake tart for five minutes. Reduce heat to 200C and bake for 20 minutes or until pastry is crisp and golden.
Cool for five minutes, then place a large, flat serving platter over the pan, and very carefully invert. Some apples may stick to the pan - just pop them back into place and nobody will be the wiser. Serve hot, with creme fraiche.
Tip It's critical to get the caramel just right, according to Thomas Keller of California's famous Bouchon Bistro. It should be ''cooked slowly so its flavours are developed, but not cooked so long that the sugar becomes bitter''.