Heat the oven to 180c/fan 160c/gas 4. Butter the inside of an ovenproof dish and add the apricots, cut-side up in a single layer and scatter the sugar over. Add the lemon juice and zest.
Split the vanilla pod in half and tuck in among the fruit. Pour over the sweet wine and cook on the middle shelf of the oven for about 40 minutes until the fruit is tender and the liquid reduced to a syrup. Serve warm with vanilla ice cream or crème fraîche.