01 - Dissolve the sourdough starter in warm water in a large mixing bowl. Stir in bread flour, whole wheat flour, salt, and sugar until a shaggy dough forms.
02 - Knead the dough for 10 minutes by hand or 7 minutes with a stand mixer until smooth and elastic, developing proper gluten structure.
03 - Gently fold in raspberries and chopped pistachios until just distributed throughout the dough. Avoid over-mixing to prevent berry smearing and color bleeding.
04 - Cover the dough and let it bulk ferment at room temperature for 8 to 10 hours or overnight until doubled in size.
05 - Turn the dough onto a lightly floured surface and divide into 8 equal pieces. Shape each piece into a tight ball and let rest for 10 minutes.
06 - Poke a hole through the center of each ball with a floured finger. Gently stretch and rotate to form an even bagel ring with a generous opening.
07 - Place shaped bagels on a parchment-lined baking sheet, cover loosely, and proof at room temperature for 1 to 2 hours until slightly puffy.
08 - Preheat oven to 425°F. Bring 8 cups of water to a boil in a large pot, then add baking soda and malt syrup or honey.
09 - Carefully drop bagels in batches into the boiling water. Poach for 1 minute per side, then transfer back to the parchment-lined baking sheet.
10 - Sprinkle with additional chopped pistachios or freeze-dried raspberry pieces while the bagels are still damp from poaching.
11 - Bake for 22 to 25 minutes until deeply golden brown with a shiny crust. Cool completely before slicing and serving.