2: Melt 100 g butter in a frying pan on medium heat, then scatter 150 g caster sugar over.
3: Add the apple pieces on top...
4: ...and leave to caramelize, stirring from time to time, until evenly done. Leave to cool.
5: Separate 500 g brioche dough into 2 pieces of about 250g (half a pound). Place one circle in the bottom of a springform tin or mould (24 cm / 9.5 inches here) and glaze around the edge.
6: Arrange the caramelized apples in the centre, keeping them away from the edge.
8: And place this on top of the bottom circle, pressing down gently around the edge to stick them together. Glaze the top with beaten egg and leave in a warm place to rise for 2 hours.
9: Preheat the oven to 390°F (200°C). Glaze the top once more and bake for 20 to 30 minutes.
10: Best enjoyed warm, if possible.
Remarks
Try to use apples with a small acidity, best for this recipe.