Not sure why more people don’t know about these.  One of my faves from Jersey.

INGREDIENTS

Dough

2 cups bread flour

1/2 teaspoon instant yeast

1 teaspoon salt

3/4 cup plus 2 tablespoons water, at room temperature

Onion-Poppy Seed Filling

2 1/4 teaspoons vegetable oil

6 tablespoons onion, chopped

3/4 teaspoon poppy seeds

1/4 teaspoon sea salt

Black pepper to taste

DIRECTIONS

Dough

Whisk flour and the yeast, then salt. Using dough hook, on low speed, gradually add the water, mixing for about 1 minute or until the flour mixture is moistened. Raise the speed to medium and continue mixing for 7 minutes. Bowl should be clean but the dough should be soft and elastic. Add a little extra flour or water if necessary. Place the dough in a lightly greased bowl, press down and spray a little oil on the top. Cover and let double about 1½ to 2 hours.

Shaping

Punch dough down and place on a floured counter. Cut into 6 equal pieces (about 3 ounces). Work with one piece at a time, keeping the remaining dough covered. Maintaining as much air as possible in the dough, round each piece by pulling the dough together to form a pouch, stretching to make a smooth skin, and pinching it together where the edges meet. Set it on a floured baking sheet or tray, pinched side down. (The rounds will be 2 1/2 inches by 1 1/2 inches high.) Flour the tops and cover with plastic wrap.

Allow the bialys to rise for about 2 hours at 75 to 80°F or until almost doubled; when pressed lightly in the center, they should keep the impression. If the dough is underrisen, it will puff up in the center instead of maintaining the characteristic hollow crater. The trick for underrisen dough is to make a small hole in the center before adding the filling. Since the dough bakes so quickly, it’s easy to test bake one to see if the dough is ready. If you want to be on the safe side, make the hole anyway.

 

Onion-Poppy Seed Filling

Heat oil in small pan. Add the onion and saute over medium heat, stirring often, for about 5 minutes or until translucent. You can get them as caramelized as you like. Remove from the heat and add the poppy seeds, salt, and pepper to taste. Cool.

Good time to preheat the oven to 475°F 30 minutes before baking. You will need to place two pans in the oven. One for baking the bialys and the other for ice just as you start baking them to create steam. Now back to the shaping of the bialys

 Holding each piece of dough with both hands, with your thumbs in the middle and almost touching, pinch the center of the dough tightly between your thumbs and first two fingers and stretch the dough to 4 1/2 to 5 inches in diameter, forming a crater in the center. Place it on the lined baking sheet and spoon 1 teaspoon of onion-poppy seed filling into the center.

Place the bialys directly on a hot baking sheet. Toss a handful of ice cubes into the sheet pan on the oven floor (this helps make your oven closer to a professional bread oven; the steam helps form a crust), and immediately shut the door. Bake for 6 to 10 minutes or until pale golden and mottled with brown spots. 

Remove the baking sheet or parchment from the oven and transfer the bialys to wire racks to cool until just warm.

I got the recipe here.