In a large bowl, crack in the egg and add the high-sugar-tolerant yeast, granulated sugar, and cold milk. Stir with chopsticks until the yeast begins to dissolve evenly.

Add the all-purpose flour and mix until a shaggy dough forms with no dry flour remaining.

Add the softened butter and knead by hand until incorporated.

Transfer the dough to a work surface and knead until smooth, elastic, and no longer sticky, about 10 minutes.

Roll the dough into a log and divide evenly into 8 portions.

Roll each portion into a smooth ball.

Flatten each ball with a rolling pin into a round wrapper, keeping the center slightly thicker and the edges thinner.

Place about 25 g of red bean paste in the center of each wrapper.

Gather the edges toward the center, pinch tightly to seal, and gently shape into a round bun.

Lightly roll each filled bun with a rolling pin to flatten slightly, about 1 cm thick. Avoid making them too thick so they fry evenly.

Dip the bun into a bowl of water to lightly moisten the surface, then remove it immediately.

Roll in breadcrumbs and gently press so the crumbs adhere evenly.

Place the coated buns on a board, cover with plastic wrap, and let them proof in a warm place until they expand to about 1.5 times their original size. Proper proofing ensures a light and fluffy interior after frying.

Heat cooking oil in a wok or deep pan to a depth of about 5 cm. Heat to medium-low, around 150–160°C. When chopsticks inserted into the oil produce steady bubbles, the oil is ready.

Gently add the proofed buns and fry over low heat, turning carefully with a slotted spoon so they cook evenly. Fry until both sides are golden brown and puffed, about 3–4 minutes.

Remove and drain on paper towels to absorb excess oil. Let rest for 2 minutes before serving.