Braided Cinnamon Buns with Vanilla Caramel Sauce

1. In the bowl of a stand mixer, add the sourdough starter, flour, milk, egg, sugar, and salt. Mix on medium speed for 5 to 7 minutes, until the dough begins to come together. Keeping the mixer on medium speed, gradually add the softened butter, about 1 teaspoon at a time, waiting until each addition is fully incorporated before adding more. Continue kneading for about 15 minutes, until the dough is smooth, elastic, glossy, and pulls away from the sides of the bowl. Shape the dough into a ball, cover the bowl with plastic wrap, and let ferment at room temperature for 5 to 8 hours, or until the dough has almost doubled in size and feels light and airy.

2. Meanwhile, prepare the cinnamon filling. In a bowl, combine all the ingredients and whisk until smooth and creamy. Set aside at room temperature.

3. Using a rolling pin, roll the dough out into a large rectangle, about 12 × 18 inches. Spread the cinnamon filling evenly over the entire surface. Fold the dough like a brochure: imagine the rectangle divided lengthwise into three equal sections, fold the right third toward the centre, then fold the left third over top, taking care not to push the filling out.

4. Once folded, cut the dough into 12 equal strips. For each strip, make two lengthwise cuts without cutting all the way through, creating three smaller strands. Braid the strands together. Tuck both ends of the braid underneath so only the prettiest part shows on top. Place each braid into a buttered muffin tin and repeat with the remaining dough.

5. Cover the muffin tins with plastic wrap and let rise at room temperature for 2 to 3 hours, until the braids are nicely puffed and slightly jiggly. Preheat the oven to 350°F (180°C), remove the plastic wrap, and bake for 20 to 25 minutes, or until the braids are deeply golden. The internal temperature should reach about 90°C. Let cool for a few minutes, then remove the braids from the pan while still warm, as the sugar hardens as it cools and makes them difficult to release.

6. While the buns are baking or cooling, prepare the caramel. In a saucepan, combine the brown sugar, 35% cream, water, and vanilla bean paste. Bring to a boil and simmer for 2 to 3 minutes, stirring occasionally, until slightly thickened. Remove from heat, then whisk in the butter and fleur de sel. Let rest for 10 minutes.

7. To serve, drizzle the buns with warm caramel and enjoy.