Chaussons aux Pommes
Melt the butter in a sauté pan. Add the apples, cover, and cook 10 minutes. Take off the lid, sprinkle over the sugar, toss in the raisins, and cook until the sugar caramelizes and coats the fruit (by now possibly a shaggy, golden mass, depending on the type of apples). Taste. Depending on the sweetness of the fruit, you may want a squirt of lemon for balance.
Roll the pastry out to a large square, about 1/4-inch/5 mm-thick. Cut into four squares, then roll each one to make it slightly rectangular (not that shape matters one bit). Spoon the fruit mixture over half of each pastry, leaving a 1 cm/5 mm margin. Brush the margins with glaze. Fold the pastry over and press the edges to seal. Set on a damp baking sheet. Slash the top of each pastry with a knife. Brush with more glaze, let rest 15 minutes in the fridge.
Heat the oven to 425°F220°C. Bake the pastry 10 minutes. Lower the heat to 375°F/190°C, and continue baking until golden, puffed up, and brown, 10 to 15 minutes longer. Cool slightly on a wire rack and serve dusted with icing sugar.