01 - In a large mixing bowl or stand mixer, combine bread flour, yeast, granulated sugar, salt, and ground cinnamon. Mix briefly to combine dry ingredients thoroughly.
02 - Add warm water and melted butter to the dry mixture. Mix until a shaggy dough forms, then knead for 8–10 minutes until smooth and elastic.
03 - Place dough in a lightly oiled bowl, cover, and let rise in a warm place until doubled in volume, approximately 1 hour.
04 - While dough rises, mix brown sugar and cinnamon in a small bowl until evenly combined for the filling.
05 - Turn dough onto a floured surface and roll out into a 10x16-inch rectangle. Spread softened butter evenly over the dough surface.
06 - Sprinkle the cinnamon-sugar filling evenly over the buttered dough. Starting from a long edge, tightly roll up the dough into a log.
07 - Cut the log into 8 equal pieces. Roll each piece into a 10-inch rope, then join the ends to form a bagel shape, pinching firmly to seal.
08 - Place bagels on a parchment-lined baking sheet, cover, and let rise for 30 minutes until slightly puffy.
09 - Preheat oven to 400°F.
10 - Bring water and honey to a boil in a large pot. Working in batches, boil each bagel for 45 seconds per side. Remove with a slotted spoon and return to the baking sheet.
11 - Bake bagels for 20–25 minutes until golden brown and cooked through. Transfer to a wire rack and cool completely.
12 - Whisk powdered sugar, milk, and vanilla extract in a small bowl until smooth and pourable. Adjust consistency with additional milk if needed.
13 - Drizzle glaze over cooled bagels. Immediately sprinkle with purple, green, and gold sanding sugar in sections to mimic traditional King Cake colors.