Known in France as Tarte Tropézienne, individual buttery brioches are split and filled with rich vanilla cream for a substantial pastry that happily works for breakfast or dessert.
To make the dough: Weigh your flour; or measure it by gently spooning it into a cup, then sweeping off any excess. In a stand mixer fitted with a paddle or bread machine programmed for manual or dough, mix and knead together all of the ingredients in the order listed, to form a smooth, shiny dough. Don't worry; what starts out as a sticky mess becomes beautifully satiny as it kneads. This dough takes longer than most to develop, so be prepared to let the dough knead for up to 15 to 20 minutes in a stand mixer. Also, we don't recommend trying to knead it by hand. If you're using a bread machine, let it complete its kneading cycle, then continue as directed below.
Form the dough into a ball (it'll be very soft), place it in a greased bowl, cover the bowl, and let it rise for 1 hour. Refrigerate the dough for several hours, or overnight. This will slow the fermentation and chill the butter, making the dough easier to shape.
To make the filling: In a medium saucepan, stir together 2 1/2 cups of the milk, the sugar, and salt. Cook over medium heat, stirring occasionally to dissolve the sugar.
In a separate heatproof bowl, whisk the cornstarch, flour, and egg yolks with the remaining 1/2 cup milk. Whisk half of the hot milk into the yolk mixture.
Pour the yolk mixture back into the saucepan through a strainer (to prevent lumps). Bring to a boil, stirring constantly with a whisk, until the mixture thickens. Use a heatproof spatula to keep the pastry cream from sticking to the bottom or corners of the pan.
When the filling boils all the way to the center of the pot, remove from the heat and strain into a bowl. Stir in the vanilla and butter. Lay a piece of buttered parchment or waxed paper on top of the cream, making sure it touches its surface, and refrigerate until needed.
To shape the brioche: Remove the dough from the refrigerator and divide it into 16 pieces. Round the pieces into balls. If you have individual brioche tins, butter them, put them on a baking sheet, and put one ball in each. If not, simply place the balls of dough on a parchment-lined baking sheet.
Cover with greased plastic and let rise until puffy looking, about 2 to 2 1/2 hours. Toward the end of the rise time, place a rack in the lower third of your oven and preheat to 375°F. Brush the tops of the brioches with the beaten egg white and sprinkle with coarse (or Swedish pearl) sugar.
Bake the brioches for 20 to 25 minutes, tenting the tops with foil after 15 minutes if they’re browning too quickly. When the centers read 190°F when measured with a digital thermometer, they’re done. Remove from the oven and let cool completely
To assemble: Fold the whipped cream into the chilled pastry cream. Slice the brioches across their circumference. Spoon a heaping 1/4 cup of filling on the bottom half of each and place the top over the filling.
Serve within an hour or so. Brioches can be filled and refrigerated for several hours, covered. Allow them to warm a bit before serving.
To make just eight filled brioches, make the entire brioche recipe, reserving half the brioches for sandwiches or dinner rolls. Make just half the pastry cream recipe, and fill eight brioches.
