To prepare the day before:

In the mixer bowl, combine flour, salt, and sugar.

Add beaten eggs, then yeast that has been diluted in milk.

Knead for 10 minutes with the hook.

Cut the butter into small pieces and add them, a few at a time, while continuing to knead.

Kneading can take 15 minutes, until the butter is well incorporated.

The dough will be heavy and soft.

Cover the mixer bowl with plastic wrap and let the dough rise for 2 hours at room temperature, then refrigerate overnight.

The next day:

Remove the dough from the refrigerator and place it on a floured surface.

Divide the dough into 2 equal parts.

Roll out each part into a rectangle 1/2 inch (1 cm) thick.

Spread each rectangle with Dulce de Leche, leaving a 1-inch (2.5 cm) border around it.

Roll each rectangle into a tight roll, starting from the long side.

Place each roll in a parchment-lined loaf pan.

Make 3 incisions on top of each brioche.

Cover the brioche with a clean cloth and let it rise for 1 hour and 30 minutes.

Preheat the oven to 350 F (180 C).

Beat the egg and milk, then brush the brioche with it.

Bake the brioche for 35 to 40 minutes or until golden brown.

Remove from oven and let cool on a rack.