Only soy protein
Soak soy protein in lukewarm water for 10 minutes, then drain.
In a bowl, combine soy protein, strong flour, sugar, salt, dry yeast, milk, eggs, and butter, and knead into a dough.
Let the dough rise for the first fermentation (about 1 hour).
Punch down the dough, shape it, and place on a pan for the second fermentation (30 minutes).
Bake in a preheated oven at 180°C (356°F) for 20 minutes.