Pour boiling water over the peaches and leave for a minute or two, then pour off the water and cover them with cold water. The skins should then be easily removed. Halve the peaches, discarding pits, and place in a single layer in an ovenproof dish, cut sides up.
Mix the macaroons with the sugar and enough of the Cointreau to make a paste. Fill the peach cavities with the paste. If nece