Try this with white peaches, if available, for a subtle variation on the original.
Directions
PREHEAT THE OVEN TO 350F and set a rack in the middle level.
Rinse, halve and pit the peaches.
Puree 2 of the peach halves in a food processor.
Place the puree in a bowl and add the sugar, crushed macaroons and the egg yolk.
Cover each peach half with this filling and place the peach halves in a buttered baking dish.
Sprinkle the remaining butter over the peaches and bake for about 30 minutes, until the peaches are baked through and the filling is a deep golden color.