In a small bowl, pour the yeast, milk, sugar and a tablespoon of flour taken from the total amount. Mix and let stand 15 min while the yeast activates. It will start to foam.
In a large bowl, pour the flour, salt, oregano then the yeast-based preparation. Mix.
Then add the eggs and butter. Mix well and knead the dough for a few minutes until it is smooth. Cover with a clean cloth and let stand at least two hours. The dough must double in volume.
Meanwhile, mix the tomatoes with the onion, salt and pepper. Check the seasoning.
For the garlic butter, melt the butter. Add the finely chopped flat-leaf parsley or chopped garlic.
Drain the mozzarella and cut it into thin strips.
Preheat the oven to 175 ° C (conventional heat).
Then remove the air from the dough and using a rolling pin, roll out the dough to form a rectangle.
Place about ¼ of the tomato sauce on the dough and spread it well. Place the mozzarella to form 3 to 4 rows of mozzarella lengthwise.
Then roll up the dough on itself. Cut it in half and braid the dough to form a babka.
Using a brush, spread the garlic butter over the babka.
Bake for 35 to 40 minutes. Then serve with the tomato sauce.