The dough:
In a large 16-cup bowl (4 liters), combine flour, sugar, yeast, and salt. Set aside.
Mix the melted butter, buttermilk, eggs, and water, then pour the mixture over the flour.
Stir until the flour is moist.
Beat the dough 40 times, scraping the bottom and sides of the bowl, until the dough forms a lumpy and sticky mass.

Cover the bowl with plastic wrap and let rise at room temperature (72F/22C), away from drafts, for 2 hours until it almost reaches the top of the bowl and has a spongy texture.
Store the dough bowl in the refrigerator, it will keep for almost 3 days.

Shaping:
Use half of the dough. This will give you 12 brioche tops.
Divide the dough into 12 equal pieces.
Take a piece of dough the size of a walnut from each piece and shape it into a teardrop shape.
Shape the larger pieces of dough into balls and place them in individual brioche or muffin silicone molds.
Use your index finger to make a hole in the center of each brioche and insert the small pieces of dough in teardrop shape.
Smooth the surface of each brioche with your hands.
Cover the brioche with a clean cloth and let rest for 40 minutes at room temperature.

Preheat the oven to 400F (200C).
Brush each brioche with beaten egg mixed with water.
Bake the brioches for 20 to 25 minutes or until they are golden brown.
Remove the brioches from the mold and let cool on a cooling rack.