1. Make the Cakes: Preheat the oven to 350°. Spray ten 2/3-cup ramekins with vegetable oil spray and set them in a roasting pan. In a large bowl, using an electric mixer, beat the butter with the sugar until pale, about 1 minute. Beat in the egg yolks 1 at a time, beating well after each addition. Working in 2 batches, at low speed, beat in the milk, lemon juice and flour.
2. In a large bowl, using clean beaters, beat the egg whites to firm peaks. Fold the whites into the batter and spoon among the prepared ramekins. Add enough hot water to the pan to reach halfway up the sides of the ramekins. Bake for about 20 minutes, until the cakes are slightly puffed and just set. Transfer the ramekins to a rack and let cool. Cover and refrigerate overnight.
3. Make the Lemon Syrup and Poppy Cream: In a small saucepan, combine the lemon zest, juice, vanilla bean and seeds and 1/4 cup of the sugar. Cook over low heat, stirring, until the sugar has melted, about 3 minutes. Remove the vanilla bean.
4. In a bowl, beat the cream with the remaining 2 tablespoons of sugar to soft peaks. Beat in the crème fraîche until firm. Stir in the 2 teaspoons of poppy seeds.
5. Run a thin knife around the edges and dip each ramekin in a bowl of very hot water for 10 seconds. Invert the cakes onto plates, spoon the lemon syrup around the cakes and top with the poppy cream. Garnish with poppy seeds and serve.