1. Combine the Wet Ingredients: In a large mixing bowl, whisk together the sourdough discard, warm water, granulated sugar, egg, and vanilla extract until well combined and smooth. The mixture should look slightly milky and uniform.

2. Mix the Dry Ingredients and Form the Dough: In a separate bowl, whisk together the all-purpose flour, salt, and ground cinnamon. Gradually add the dry ingredients to the wet ingredients, mixing with a wooden spoon or your hands until a shaggy dough forms. Turn the dough out onto a lightly floured surface and knead for 5-7 minutes until it’s smooth and elastic. It should spring back slightly when poked.

3. Incorporate the Raisins and First Rise: Gently knead the raisins into the dough until evenly distributed. Place the dough in a lightly oiled bowl, turning it once to coat. Cover the bowl with plastic wrap or a damp kitchen towel and let it rise in a warm place for 2-4 hours, or until doubled in size. Alternatively, you can refrigerate it overnight for a slower, more flavorful rise.

4. Shape the Bagels: Once risen, gently punch down the dough and divide it into 8 equal pieces. Roll each piece into a smooth ball, then use your thumb to poke a hole in the center of each ball. Gently stretch the hole to about 1-1.5 inches in diameter, creating the classic bagel shape. Place the shaped bagels on a parchment-lined baking sheet.

5. Prepare for Boiling and Baking: Preheat your oven to 425 F (220 C). Bring 2 quarts of water to a rolling boil in a large pot, then add the baking soda. In a small bowl, whisk together the egg and 1 tablespoon of water for the egg wash.

6. Boil and Bake the Bagels: Carefully drop 2-3 bagels into the boiling water at a time, ensuring they don’t overcrowd the pot. Boil for 30 seconds on each side, then remove with a slotted spoon and place them back on the parchment-lined baking sheet. Brush the tops of the boiled bagels with the egg wash. Bake for 20-25 minutes, or until golden brown and cooked through. Let cool on a wire rack before serving.