Tangzhong (Water Roux)

• 3 tablespoons bread flour

• ½ cup whole milk

Dough

• 3 cups bread flour, plus more for dusting

• ¼ cup granulated sugar

• 1½ teaspoons fine sea salt

• ½ cup active sourdough starter (100% hydration, fed and bubbly)

• ½ cup warm whole milk (95°F / 35°C)

• 1 large egg, room temperature

• 4 tablespoons unsalted butter, softened and cubed

Natural Color Powders

• 1 teaspoon beet powder (pink/red)

• 1 teaspoon turmeric powder (golden yellow)

• 1 teaspoon spirulina powder (green)

• 1 teaspoon butterfly pea flower powder (violet/blue)

Egg Wash

• 1 large egg

• 1 tablespoon whole milk

1. Make the tangzhong: Whisk together the bread flour and milk in a small saucepan over medium-low heat. Cook, stirring constantly, until the mixture thickens into a smooth paste and registers 150°F (65°C), about 3-4 minutes. Transfer to a bowl, press plastic wrap directly onto the surface, and cool to room temperature.

2. Mix the dough: In the bowl of a stand mixer fitted with the dough hook, combine the bread flour, sugar, and salt. Add the cooled tangzhong, sourdough starter, warm milk, and egg. Mix on low speed until a shaggy dough forms, about 2 minutes. Increase to medium and knead 5 minutes.

3. Add butter: With the mixer running on medium, add the softened butter one tablespoon at a time, waiting until each piece is fully incorporated before adding the next. Continue kneading until the dough is smooth, elastic, and passes the windowpane test, 8-10 more minutes.

4. Divide and color: Turn the dough onto an unfloured surface and divide into 5 equal portions (about 130g each). Flatten one portion, sprinkle on beet powder, and knead until the color is uniform. Repeat with the remaining colors, leaving the fifth portion plain. Lightly butter your hands if the dough becomes sticky.

5. First fermentation: Shape each colored portion into a smooth ball and place in separate lightly greased bowls. Cover with plastic wrap. Let rise at room temperature until puffy and roughly doubled, 4-6 hours, or refrigerate overnight (8-12 hours) for deeper sourdough flavor.

6. Shape the loaf: Lightly flour your work surface. Roll each colored portion into a rope about 18 inches long. Lay all 5 ropes side by side, pinch together at one end, and braid or twist them together. Tuck both ends under and nestle the loaf into a greased 9°5-inch loaf pan.

7. Second rise: Cover loosely with plastic wrap and let rise until the dough crowns about 1 inch above the rim of the pan, 2-4 hours at room temperature.

8. Bake: Preheat the oven to 350°F (175°C). Gently brush the loaf with egg wash. Bake 30-35 minutes, until deep golden brown and an instant-read thermometer inserted in the center reads 190°F (88°C). Tent loosely with foil after 20 minutes if browning too quickly.

9. Cool: Let cool in the pan for 10 minutes, then turn out onto a wire rack. Rest at least 1 hour before slicing, this allows the crumb to fully set and the colors to stay vivid when cut.