01 - In a large bowl, combine the active sourdough starter, lukewarm water, and sugar. Stir vigorously until the sugar completely dissolves and the mixture is uniform.
02 - Add bread flour, whole wheat flour, and fine sea salt to the starter mixture. Mix with a wooden spoon or your hands until a shaggy, rough dough forms and no dry flour remains visible.
03 - Turn the dough onto a lightly floured surface and knead for 8–10 minutes. During the final 2 minutes, work in the vegetable oil until the dough becomes smooth, elastic, and slightly tacky but not sticky.
04 - Gently fold the fresh or frozen raspberries into the dough, handling minimally to keep berries as whole as possible. The dough will appear sticky and develop a pink marbled appearance.
05 - Transfer the dough to a lightly greased bowl, cover with plastic wrap or a damp towel, and let rise at room temperature for 6–8 hours until doubled in size.
06 - Turn the risen dough onto a lightly floured surface. Divide into 8 equal portions using a bench scraper or knife, weighing approximately 100g each.
07 - Form each portion into a smooth ball by tucking edges underneath. Poke a hole through the center with your finger and gently stretch and rotate to create an even ring with a 2-inch center opening.
08 - Place shaped bagels on a parchment-lined baking sheet, cover with a clean towel, and let proof for 1–2 hours at room temperature. Alternatively, refrigerate overnight for deeper sourdough flavor development.
09 - Preheat oven to 425°F with oven rack positioned in the center.
10 - Bring 12 cups of water to a rolling boil in a wide pot. Stir in honey (or barley malt syrup) and baking soda if using until fully dissolved.
11 - Working in batches of 2–3, carefully lower bagels into the boiling water. Cook for 45–60 seconds per side, then remove with a slotted spoon, allowing excess water to drain before returning to the baking sheet.
12 - Immediately sprinkle boiled bagels with Demerara sugar or poppy seeds while surfaces are still damp for better adhesion.
13 - Bake for 22–25 minutes until bagels achieve a deep golden brown color and sound hollow when tapped on the bottom. Rotate the baking sheet halfway through for even browning.
14 - Transfer baked bagels to a wire rack and let cool completely for at least 30 minutes before slicing or serving to prevent gummy texture.