Sprinkle the work surface with flour and then drop the risen dough. Divide the dough into 8 equal parts.
Shape each part into a tight ball by shaping it a bit by your hands and then rolling it on the work surface keeping the dough within your fingers.
Place the rolls on a lightly greased tray and let it rise for about an hour more or till it leaves a depression when pressed with the fingers. Cover the tray with a cloth when rising.
Work on one piece at a time, while you keep the others covered so they don’t dry out. When the rolls are ready, pick them up one at a time and using your fingers, form the depression in the middle. Hold the roll like a steering wheel with your thumbs in the middle and your fingers around the edges. Pinch the dough between your thumb and fingers, rotating as you go and gradually making the depression wider without actually poking a hole through. This step reminded me of making the outer covering of the Kozhukattai's :)
Once shaped the bialy should be about 4 inch wide, with the depression being about 3 inches wide and a 1 inch border. Prick the center of the bialy with a fork so that it does not puff up while baking.
Place the shaped Bialys on a parchment lined (or lightly greased) tray. Place the caramelized onion filling in each of the depression. If using milk, brush the outer ring of the bialy with the milk.
Bake the bialys at a preheated 450 F oven for about 15 mins, until they are golden brown.
Cool on a cooling rack and then serve warm.