Mix Dough: In a large (4-quart) container, combine water, buttermilk, yeast, sugar, eggs, and salt. Stir in flour with a dough whisk until just combined (no kneading). Add raisins; mix gently.
Rest Dough: Loosely cover and let rest at room temperature for 2 hours. Use immediately or refrigerate up to 24 hours.
Prepare Pans: Grease three 8½x4½-inch loaf pans or save some dough to make into loaves later.
Shape Loaves: On a lightly floured surface, divide dough into three equal portions. Roll each into a ½-inch-thick rectangle (~8x12 inches). Sprinkle each with one-third of the cinnamon sugar mix. Roll tightly along the long edge, pinch seam to seal, and tuck ends under. Place seam-side down in prepared pans.
Second Rise: Cover and let rise until doubled, ~1 hour.
Bake: Preheat oven to 350° F (175°C). Whisk egg wash ingredients; brush over loaves. Bake 45 minutes until golden and hollow-sounding when tapped (190° F internal).
Cool: Remove from pans and cool on a wire rack for at least 1 hour before slicing.
Video
Notes
The recipe makes 3 loaves (8 1/2 X 4 1/2-inch pans) and can be divided if desired