Sift the flour into a large bowl, make a well in the center, and add the yeast, a pinch of sugar, and 2 tablespoons of warm milk. Let sit for 10 minutes until foamy.
Add the remaining sugar, salt, egg, butter, vanilla, and lemon zest. Pour in the rest of the milk, knead into a smooth dough, and let rise for 1 hour until doubled in size.
Roll the dough out to 1 cm thickness and cut out 5 circles (about 9 cm in diameter). Place them on a baking sheet, cover, and let rest for 30 minutes.
Preheat the oven to 180°C (350°F). Brush the dough with the beaten egg mixture and sprinkle with pearl sugar. Bake for 15-20 minutes until golden brown, then let cool completely.
For the crĂšme mousseline, heat the milk with the vanilla pod and seeds. Whisk egg yolks, sugar, and cornstarch in a bowl. Gradually stir in the hot milk, return the mixture to the pot, and cook over medium heat until thickened. Let cool completely.
Beat the soft butter and gradually fold in the cooled cream until light and fluffy. Chill the cream before using.
Cut the cooled pastries in half horizontally. Pipe the crĂšme mousseline onto the bottom halves and place the top halves back on. Dust with powdered sugar and serve.
To make the dough, mix flour, yeast, sugar, salt, egg, butter, vanilla, and lemon zest with warm milk. Knead until smooth, let rise until doubled, then shape into small rounds, let rise again, and bake until golden brown.
CrĂšme mousseline is a rich cream made by combining pastry cream with whipped butter. It's made by cooking milk with vanilla, then mixing it with egg yolks, sugar, and cornstarch, cooling it, and folding in softened butter to create a light, fluffy filling.
Once the brioche dough is baked and cooled, slice each round in half. Pipe the chilled crĂšme mousseline onto the bottom halves, then place the top halves back on. Dust with powdered sugar before serving.
Yes, you can prepare the brioche and crĂšme mousseline a day in advance. Store the baked brioche at room temperature and the cream in the refrigerator. Assemble just before serving for the freshest taste.
