Blanch peaches in boiling water for 2 minutes.
Plunge into cold water and remove skins, then cut in half and remove pits.
Carefully scoop out some of the peach pulp from each half, leaving a shell 172 cm thick.
Mash pulp and reserve.
Cream together 2 tablespoons of the butter and 2 tablespoons of sugar.
Add macaroon crumbs, peach pulp, egg yolk and liqueur, and mix well.
Fill peach halves with this mixture, then place them in a buttered baking dish with the water or wine in the bottom.
Dot each peach half with the remaining butter and place an almond on top.
Sprinkle remaining sugar on the almond only, and bake in a preheated 350°F./180°C oven for 30 minutes (15 minutes for canned peach halves) until tender but still firm.
Serve hot or cold.