Add the type 0 flour, sugar, small egg, milk, lemon zest, vanilla, and crumbled fresh baker's yeast to the mixing bowl.

Knead the dough for 5 minutes until the ingredients are combined.

Add the salt and incorporate the unsalted butter gradually until the dough is smooth and elastic.

Shape the dough into a ball and place it in the dough container.

Let the dough rise until nearly doubled in volume, about 90 minutes.

Chill the covered dough for 240 minutes.

Shape the Bavarian butter into a 20 cm by 20 cm square.

Roll the cold dough into a 20 cm by 40 cm rectangle.

Enclose the butter square inside the dough rectangle.

Roll and fold the dough into thirds; repeat until 3 sets of letter folds are completed without resting.

Chill the laminated dough for 60 minutes.

Freeze the dough for 30 minutes for cleaner cutting.

Cut the dough into strips and press the strips lightly with the rolling pin on a floured work surface.

Roll each strip into a spiral and place the spirals in the loaf pans.

Let the shaped brioches rise for 90 minutes.

Bake the brioches at 180°C for 30 minutes until deeply golden.

Heat the water and sugar for syrup until dissolved.

Brush the warm brioches with the sugar syrup.