Far breton, prune custard from Brittany, a recipe from Gourmetpedia

Ingredients

• - 200 g pitted prunes
• - 5 eggs
• - 130 g sugar
• - 1 packet vanilla sugar (30 ml)
• - 220 g flour
• - 750 ml / 3 cups whole milk
• - 20 g half-salt butter, plus some extra shavings