01 - Combine active sourdough starter, lukewarm water, and sugar in a large mixing bowl. Stir continuously until sugar completely dissolves and mixture appears uniform.
02 - Add bread flour, whole wheat flour, and sea salt to starter mixture. Mix with a wooden spoon or hands until shaggy dough forms and no dry flour remains visible.
03 - Turn dough onto lightly floured work surface. Knead firmly for 8–10 minutes, pushing forward and folding back, until surface becomes smooth and elastic. Drizzle vegetable oil over dough during final minute of kneading.
04 - Gently fold raspberries into dough using minimal pressure to maintain whole berries. Dough will appear sticky and show marbled raspberry streaks throughout.
05 - Place dough in lightly oiled bowl, cover with plastic wrap or damp towel. Let rise at room temperature for 6–8 hours until doubled in volume.
06 - Turn risen dough onto floured surface. Divide into 8 equal pieces using a bench scraper or sharp knife, approximately 4 oz each.
07 - Form each portion into a smooth ball by tucking edges underneath. Poke thumb through center, then gently rotate and stretch to create 2-inch hole, forming classic bagel shape.
08 - Arrange bagels on parchment-lined baking sheet, cover with clean towel. Proof at room temperature for 1–2 hours until slightly puffed. For optimal flavor development, refrigerate overnight.
09 - Set oven to 425°F and position rack in center position.
10 - Bring 12 cups water to rolling boil in wide pot. Stir in honey and baking soda if using until fully dissolved.
11 - Working in batches of 3–4, lower bagels gently into boiling water. Boil for 45–60 seconds per side. Remove with slotted spoon, allowing excess water to drain, then return to parchment-lined sheet.
12 - Immediately sprinkle wet bagel tops with Demerara sugar or poppy seeds while surface remains tacky from boiling.
13 - Bake for 22–25 minutes until bagels develop deep golden brown crust and sound hollow when tapped bottoms. Transfer to wire rack and cool completely before slicing.