Preparation

• In a bowl, soak the prunes in the Armagnac for about an hour, stirring occasionally. Heat the oven to 375°F. Butter a 9-inch cake or pie pan.
• In a large bowl, whisk the eggs and sugar until lightly frothy and the sugar is dissolved. Sprinkle or sift in the flour and cinnamon; whisk until smooth. Gradually add the cream and milk, whisking just until smooth. Melt 2 Tbs. of the butter and stir it into the batter. Arrange the prunes in the prepared cake pan. If there’s any unabsorbed Armagnac, sprinkle it over the prunes. Pour the batter over the fruit and dot it with small bits of the remaining 2 Tbs. butter.
• Bake until evenly puffed and golden brown and a skewer comes out clean, about 40 minutes. Immediately sprinkle with the vanilla sugar. Serve warm.