Overnight Ube Cinnamon Rolls

Ingredients

Buttermilk Dough

450 g all-purpose flour
3 tbsp granulated sugar
1.5 tsp instant yeast
0.5 tsp baking soda
1 tsp kosher salt
240 ml buttermilk, warmed to about 50 °C
1 large egg, at room temperature
60 ml vegetable oil

Ube Filling

55 g ube halaya jam
55 g crème fraîche
2 tbsp granulated sugar
2 tsp ground cinnamon
1 tsp ube extract
pinch kosher salt

Crème Fraîche Glaze

45 g crème fraîche
15 ml whole milk
1 tsp pure vanilla extract
85 g confectioners' sugar

Instructions

In a large bowl, whisk together the flour, sugar, instant yeast, baking soda, and salt. Set aside.
In a large liquid measuring cup, whisk together the lukewarm buttermilk (warm-bath temperature, not hotter, so the yeast is not killed), egg, and vegetable oil. Set aside.
Make a well in the center of the dry ingredients and add the liquid ingredients. Stir with a wooden spoon or rubber spatula until combined. Transfer to a lightly floured counter and knead for 10 minutes until the dough is smooth and elastic. If the dough is sticking, add up to 60 g extra flour as you knead, but do not overdo it.
Transfer the dough to a greased bowl, cover with plastic wrap, and refrigerate overnight, until the dough has doubled in size.
Once the dough has doubled, transfer to a lightly floured counter and roll into a rectangle about 30 × 50 cm. The longer the rectangle, the more attractive the rolls.
In a small bowl, whisk together the ube halaya jam, crème fraîche, sugar, cinnamon, ube extract, and a pinch of salt until well combined and a homogenous purple color. Spread the ube mixture evenly over the rolled dough, including the edges.
Working widthwise, roll the dough into a log, pinching the edges to seal. Cut into 7 to 8 pieces, each about 5 cm wide. Place cut sides down in a 23 cm deep-dish pan in a flower shape. Cover with plastic wrap and let rise in a warm place until the edges are rounded and touching, about 1 to 1 1/2 hours.
Preheat the oven to 175 °C. Bake for 30 to 35 minutes, until the edges of each bun are golden. A skewer inserted in the center bun should come out clean, without dough. If the tops brown too quickly, cover with aluminum foil and continue baking. Let cool on a wire rack.
While the rolls cool, make the glaze: beat the crème fraîche, milk, and vanilla on low speed until combined. Add the confectioners' sugar all at once and beat until fluffy and of drizzling consistency. Drizzle over the warm rolls and spread with a spatula or butter knife.

Notes

You need ube halaya jam and ube extract. Ube extract can be substituted with vanilla, but the rolls will be less purple and less flavorful.

Because ube is subtle, some prefer omitting the cinnamon for a stronger ube flavor.

If baking in a 25 cm cast-iron pan, place only about 5 buns in the pan so they expand sideways; bake extras on a sheet pan with space between them.

Sour cream or cream cheese can replace crème fraîche.

Foiling the tops mid-bake helps keep them from burning.