Onion Bialys

In large bowl, dissolve sugar in warm water. Sprinkle in yeast; let stand until frothy, about 10 minutes.

Stir in whole wheat flour and salt. Gradually add bread flour, mixing with wooden spoon to form shaggy dough. Turn out onto lightly floured surface; knead until smooth and elastic, about 15 minutes.

Place in greased bowl, turning to grease all over. Cover with plastic wrap; let rise in warm place until doubled in bulk, about 2 hours.

Punch down dough, pull edges to centre and pinch to form ball. Turn dough and cover; let rise until doubled in bulk, about 1-1/2 hours (or place in large bowl, cover and refrigerate overnight).

Punch down dough; divide in half. Shape each into ball; cover and let rest for 15 minutes. Shape each into 10-inch (25 cm) long rope; cut each rope into
5 pieces. Shape each into ball, stretching and pinching dough underneath to smooth tops. Flatten to about 3 inches (8 cm) in diameter. Place on floured work surface; cover with damp cloth and let rise until doubled in bulk, about 45 minutes.

In bowl, mix together onion, bread crumbs, poppy seeds and oil; set aside.

Press well in centre of each bun. Stretch well to 2 inches (5 cm) in diameter with 1/4-inch (5 mm) thick base, being careful not to deflate dough around well. Spoon heaping 1 tsp (5 mL) onion mixture into each well, pressing to adhere. Cover and let rise for 30 minutes.

Heat bread stone, pizza stone or baking sheet on centre rack of 450°F (230°C) oven. With floured spatula, carefully slide half of the bialys, 1 at a time, onto heated stone. Spray inside of oven with 1/3 cup (75 mL) water, avoiding lightbulbs and closing door quickly to seal in steam. Bake until golden brown, 13 to 15 minutes. Transfer to rack and let cool. Repeat with remaining bialys. Serve warm or at room temperature. (Make-ahead: Store in airtight container for up to 24 hours or freeze for up to 2 weeks.)