Add the flour, yeast, salt and water in a food processor and knead till the dough comes together.
Knead by hand for about 5-7 minutes or until you get a smooth and failry stiff dough. You can use your stand mixer or bread machine to knead.
Place the dough in a lightly greased bowl and cover it. Keep in a warm place for about 1 1/2 hours or until it's just about doubled.
To make the filling, heat a pan and add olive oil. Add the garlic, onion and fry over medium heat till it's dark brown. Add poppy seeds, pepper, salt and combine. Set aside to cool.
Gently deflate the dough and divide it into 8 balls. Take a ball and shape into 4" to 5" circles with a small rim. Keep the remaining dough covered.
Place the shaped circles on a parchment-lined or lightly greased baking sheet. Prick the center using a fork. Place about a tablespoon of the onion filling into the center of each bialys.
Preheat the oven to 230 C | 425 F.
Top the bialys with a sheet of parchment or aluminum foil and then with another baking sheet.
Bake the bialys for 4 minutes. Remove them from the oven, and remove the baking sheet and parchment or foil.
Return the bialys to the oven, and bake for an additional 7 minutes, till they're a slightly golden brown. Remove from the oven and cool on a rack.