Preheat the oven to 180°C/350°F/Gas mark 4.
Peel, core and slice the apples, and put them in a pan with the caster sugar and 25g/1oz of the butter. Add 3 tablespoons water, cover the pan and poach gently over a low heat for 10 minutes. Remove the lid, stir and turn up the heat, continuing to cook until you have a thick purée. Stir in the lemon juice and apricot jam, and reserve.
Melt the remaining butter and cut the crusts off the slices of white bread. Cut the bread into fingers, brush with the butter and use them to line a 20cm/8in mould or soufflé dish. Pour in the apple purée, and cover the top with more butter-soaked bread.
Place the dish on a baking sheet, and bake in the oven for 35 minutes until the top is crisp and golden brown. Allow to cool for 10 minutes before sliding a palette knife round the edge and turning out onto a serving dish. Cut into wedges and serve with cream or ice cream.