Nancy Silverton's Viennese Cream Brioche

I had some leftover brioche dough in the fridge, so I made these Viennese Cream Brioche. They are so simple to make but are amazing good. According to Nancy Silverton, these buns are "A sublime combination of flavor and texture, this super simple pastry is everyone's favorite. Julia Child was brought to tears the first time she tasted them."

The recipe is from Nancy Silverton's Pastries from the La Brea Bakery.

The brioche dough is made from 3 1/2 cups of flour, and I think that any brioche recipe would work. Puff pastry might be nice as well.

Viennese Cream Brioche
1 recipe brioche dough, chilled
1 stick plus 1 tablespoon unsalted butter, chilled and cut into 12 square pats
1 extra-large egg lightly beaten
1/4 cup large crystallized sugar or granulated sugar
2 cups plus 2 tablespoons creme fraiche or sour cream
1/4 cup granulated sugar

Separate the dough into twelve 3-ounce pieces. On a lightly floured work surface, roll the dough into 2-inch balls. Flatten the balls into 5-inch discs, about 1/4-inch thick. Place on a parchment-lined baking sheet and set aside in a warm place to proof, about 1 hour, until spongy to the touch. Flip the discs over and allow them to finish rising, about 1 more hour.

Adjust the oven rack to the lower position and preheat the oven to 350F.

Press a pat of butter into the center of each disc. Brush around the rim with the beaten egg and sprinkle 1 teaspoon of the crystallized sugar around the edge. Spoon about 3 tablespoons of creme fraiche over the butter in a mound, and sprinkle 1 teaspoon of granulated sugar over it.

Place 2 inches apart on the parchment-lined baking sheet and bake for 20 to 30 minutes, until lightly browned and the center is set.