Bialys

Whisk dough dry ingredients together. Mix in water and knead on medium-low until the dough is smooth and elastic and clears the sides of bowl but sticks to bottom, ~8 min.

Transfer dough to a well-floured counter. Using well-floured hands, knead dough to form smooth, round ball, ~30 sec. Place dough seam side down in lightly greased bowl or container, cover and let rise 1-1.5 hours. Unrisen dough can be refrigerated at least 8 hours or up to 16 hours. Let sit at room temp for 1 hour before shaping.

Press dough down to deflate. Transfer to lightly floured counter and divide into 12 pieces (~3 oz), loosely cover with plastic wrap.

Form pieces into balls. Cover loosely with plastic wrap and let rest for 30 min.

Create the filling by cooking down the onions in salt and oil until softened and golden brown, ~10 min. Turn off the heat and mix in poppy seads.

Line 2 baking sheets with parchment paper and lightly flour. Press dough balls into 5-in rounds of even thickness and arrange on sheets. Cover loosely with plastic, let rise until puffy, ~15-20 min.

Adjust oven racks to upper-middle and lower-middle and heat to 475. Grease and flour bottom of round 1-cup measuring cup (3-in diameter). Press firmly into the center of each dough round until the cup touches the sheet to make indentation (flour cup as needed).

Divide filling among bialys (1 heaping Tbsp each) and smooth with back of spoon. Bake until light golden brown, 15-20 min, rotating half way between. Cool for 15 min before serving.