Kopi Roti-Style Malaysian Coffee Buns

Make topping: Combine softened butter and powdered sugar in a large bowl. Whisk together until pale, fluffy, and light. Add flour, cornstarch, and egg. Dissolve coffee in the warm water, and add to the bowl. Whisk together until smooth and fully combined. Place mixture in a piping bag and keep chilled until ready to use.

Bloom yeast: Mix together yeast, sugar, and warm milk in a small bowl. Let sit for 5 minutes.

Make dough: Add flour, sugar, egg, and salt to the bowl of a stand mixer fitted with a dough hook. Combine on low speed, then add the yeast mixture. Turn mixer to medium speed and run for 2 minutes or until a rough dough forms. Turn off the mixer and add the softened butter. Turn mixer back on to medium speed for 8-10 minutes or until the dough is smooth and elastic.

Proof dough: Remove bowl from mixer and tightly cover it in plastic wrap. Let dough rise for 1 hour or until doubled in size.

Divide dough: Turn dough out onto a floured work surface. Divide into eight equal pieces. Roll each piece into a ball, and keep them covered under plastic wrap while you shape each bun.

Shape buns: Working one piece at a time, flatten the ball into a circle. Place a cube of butter in the center. Gather the edges of the dough, sealing the butter inside. Roll back into a ball and rest on a baking sheet lined with parchment paper, seam-side down.

Proof buns: Once 8 buns have been shaped, cover them with plastic wrap. Let buns rise for 40 minutes or until doubled in size.

Prepare for baking: Preheat oven to 350°F.

Pipe coffee topping: Snip off a ½-inch opening off your piping bag. Working one piece at a time, position your piping bag on top of a bun. Slowly pipe a tight spiral, starting at the center then working your way outwards until you reach halfway down the bun. Repeat until all buns have a topping.

Bake: Place buns in preheated oven and bake for 15 minutes or until lightly golden. The topping will melt around the bun, forming a shell.