How to Make It
In a medium saucepan, combine the wine and sugar and bring to a boil. Simmer over moderately high heat until reduced to 1 cup, about 18 minutes.
In another small saucepan, bring the milk and cream to a boil. In a large bowl, beat the egg yolks. Gradually beat in the hot cream. Add the chocolate and butter; let stand for 2 minutes, then stir until smooth. Stir in half of the wine syrup. Pour the pudding into six 6- to 8-ounce heatproof glass jars or glasses. Refrigerate for at least 2 hours or overnight.
In the bowl of a stand mixer set over a saucepan of simmering water, whisk the egg whites with the sugar and cream of tartar until warm and the sugar is dissolved, 3 to 5 minutes. Let cool slightly. In the mixer, beat the whites at medium-high speed until firm, glossy peaks form, about 2 minutes.
Scrape the meringue into a pastry bag fitted with a large star tip and pipe it onto the puddings. Using a kitchen torch, brown the meringue. Serve with the shortbreads and remaining wine syrup.
If you don’t have a torch, pipe the meringues onto a foil-lined baking sheet. Broil 6 inches from the heat until lightly browned, about 1 minute. Using a small spatula, set the meringues on the puddings just before serving.