Soft red bean bread with sweet azuki filling is a comforting bakery dessert. A family treat with naturally sweet, fresh red bean paste.
Warm the milk until just lukewarm (about 105°F), then add sugar and instant yeast. Stir and let it sit for 5–10 minutes until foamy.
In a large mixing bowl, combine flour and salt. Gradually add the yeast mixture, one beaten egg, and softened butter. Knead for 8–10 minutes until the dough becomes smooth and elastic.
Cover the bowl with plastic wrap and let the dough rise in a warm place for 60–90 minutes, until doubled in size. Avoid drafts for even rising.
Punch down the dough, divide into 6 equal balls, and let them rest covered for 10 minutes.
Flatten each dough ball into a disk, place about 2–3 tbsp red bean paste in the center, and pinch the edges closed to seal. Shape into smooth balls with the seam side down.
Arrange buns on a parchment-lined baking sheet, loosely cover, and let rise for another 30 minutes. Preheat oven to 350°F (175°C) during this proofing.
Bake for 18–22 minutes on the center rack until golden brown. Optionally, brush with melted butter after baking for a soft sheen.
Cool the breads slightly before serving for best texture and to avoid burning your mouth.