Dough
½ cup + 1 tbsp milk
1 egg
2⅓ cup bread flour, normal plain will do too
2 tbsp caster sugar
½ tsp salt
0.5 oz butter, softened
1 tsp active dry yeast

Filling and topping
9 oz of red bean paste, divided into 9 balls

(I've used Azuki beans and made the paste from scratch, this will take a few hours to make but great if you can't find it in shops.)

1 tbsp melted butter/vegetable oil
black sesame seeds

Instructions
I used a breadmaker for this, similar to making brioche dough:

Add ingredients into the breadmaker pan following instructions on your breadmaker for dough setting.
When dough is ready, remove dough from pan and divide it into 9 equal sized balls.
Allow the dough balls to rest covered for 15 minutes.
Gently flatten dough balls and place the red bean filling in the centre. Carefully fold dough over to enclose the red bean paste. Shape into a ball and lightly flatten it. Using your finger, make a slight indentation in the centre of each flattened ball.
Use a pair of kitchen scissors to cut 5 deep cuts around the flattened ball to make a floral shape (optional).
Preheat oven to 190°C.
Set aside on a non-stick baking sheet, covered, for about 15 minutes.
When the buns have almost doubled in size, bake them in the centre rack of the preheated oven for 15 minutes.
Once buns are golden brown, remove them from the oven and brush them with melted butter. This gives the buns a nice shiny golden colour. Sprinkle sesame seeds on top.
Cool buns on a wire rack.

Alternatively you can use a standing mixer with dough hook:

Mix milk, egg, flour, salt and sugar together in the bowl of a standing mixer.
Add the soften butter and knead for 8 - 10 minutes using a dough hook. The dough is ready when it is smooth and elastic.
Transfer dough to a clean bowl. Cover with plastic wrap and allow to rise in a warm place till it doubles in size.
Divide dough into 9 pieces.
Follow the rest of the instructions from the breadmaker portion on shaping the dough.

"Thank you" and Credit to Theresa of Delicacious