Combine water, sugar, lemon juice, and vanilla into a wide saucepan and heat gently to dissolve the sugar. Bring the pan to the boil for about 5 minutes, then reduce heat to simmer. Halve the peaches and remove the pits, if possible (if they aren’t easily removed, don’t worry — you can pull them out after poaching). Poach the peach halves in the sugar syrup for about 2 to 3 minutes on each side depending on the ripeness of the fruit. Test the cut side with the sharp point of a knife and, once they are soft, use a slotted spoon to transfer them to a plate. Continue working in batches until all peaches are poached. Allow them to cool a bit, then remove the skins and any remaining pits.

To make the raspberry sauce, combine the berries, confectioners’ sugar, and lemon juice in a blender or a food processor. Pour through a strainer to remove the raspberry seeds (optional). Place two poached peach halves into each bowl, add a large scoop of ice cream, and drizzle with raspberry sauce.