Warm 100 ml of the milk until lukewarm, about 35–40°C (95–104°F). Stir in the baker's yeast and let it stand until foamy, about 10 min.

Peel the ripe plantain and mash it into a smooth purée. Set the mashed plantain aside.

Combine the wheat flour, salt, and ground turmeric in a large mixing bowl. Make a well in the center.

Add the mashed plantain and yeast mixture to the flour mixture. Mix until a shaggy dough forms.

Melt the butter and add it to the dough. Knead until the dough is smooth and elastic, about 8–10 min.

Cover the dough and let it rise in a warm place until doubled in size, about 60 min. Line a baking sheet while the dough rises.

Divide the risen dough into 8 equal portions. Shape each portion into a smooth round bun and place them on the baking sheet.

Cover the shaped buns and let them rise until puffy, about 30 min. Preheat the oven to 180°C (350°F).

Whisk the egg with the remaining 100 ml milk. Brush the mixture evenly over the risen buns.

Bake the buns until golden brown and cooked through, about 15–18 min. Transfer them to a wire rack to cool.