01 - Mix active sourdough starter, water, and sugar in a large bowl until dissolved.
02 - Add bread flour, whole wheat flour, and salt. Mix until shaggy dough forms.
03 - Knead on lightly floured surface for 8-10 minutes until smooth. Incorporate oil towards the end.
04 - Gently fold in raspberries, keeping them as whole as possible. Dough will be sticky and slightly marbled.
05 - Transfer dough to greased bowl, cover, and let rise at room temperature for 6-8 hours until doubled.
06 - Turn dough onto floured surface. Divide into 8 equal pieces.
07 - Shape each piece into a ball, poke hole in center, and gently stretch to form bagel shape.
08 - Place on parchment-lined baking sheet, cover with towel. Proof for 1-2 hours or refrigerate overnight.
09 - Preheat oven to 425°F.
10 - Bring 3 L water to boil in wide pot. Stir in honey and baking soda if using.
11 - Boil bagels in batches for 45-60 seconds per side. Remove with slotted spoon and return to baking sheet.
12 - Sprinkle with Demerara sugar or poppy seeds if desired.
13 - Bake for 22-25 minutes until golden brown. Cool on wire rack before serving.