Preheat oven to 475 degrees F. Flour a baking sheet and set aside.

Cut dough into 6 (for larger bialys) or 8 (for smaller ones) equal pieces.

Shape each piece of dough into some semblance of a 4" or 5" circle (they need not be perfect, in fact it's better if they aren't). Let the dough rest for 10-15 minutes.

While the dough rests, heat the oil in a large frying pan over medium heat.

Add the chopped onion and cook for 7-9 minutes, or until very soft and golden-brown.

Add the poppy seeds and salt and pepper to taste.

Remove from heat and allow to cool for at least 5 minutes.

Press about 1 tablespoon of the onion mixture (more, if it will fit) into the well you created in each bialy.

Bake for 12-14 minutes, or until the bialys are golden-brown with crisp bottoms.