Microwave milk for 30s, add in the yeast and stir quickly. Leave it for 2-3 minutes
Combine all purpose flour, bread flour and sugar into standing mixer
Pour in the milk (make sure to get all of the yeast at the bottom)
Mix on medium low until it forms a rough dough
Add in beaten egg and mix until it's incorporated
Add in softened butter and salt, mix until all ingredients have been incorporated. It might take a bit longer for dough to come together but be patient. The dough will be a bit wet.
Once it forms a dough, cover and place into a warm place to proof. I used my oven on proofing mode or you can use the oven with a bowl of hot water.
Proof for 1 hour to 1 hour 10 minutes or until it's double in size
Cookie crust
Prepare the cookie crust by mixing the butter with sugar. Make sure to incorporate all sugar in before moving onto the next step.
Add in egg and cake flour, milk powder, baking powder and baking soda. Mix until it's incorporated.
Roll into individual balls, it should make about 10-12 and place onto a baking tray with silicone mat or teflon sheet
Freeze for at least 30 minutes.
Making the pineapple bun
On a clean surface, sprinkle some flour, flatten the dough to deflate some of the air and roll into a long log.
Divide into rough 10-12 pieces. If it is not even, you can cut a small piece from a large piece and incorporate to the smaller pieces
Tuck the edges under and cup your hand over the dough. Move in a circular motion with the dough to shape into a round bun.
Once all the dough is shaped, cover and set aside and rest for about 10-15 minutes
Take the cookie dough out of the freezer and let it rest in the fridge for about 10 minutes
Place the individual cookie crust onto the teflon sheet. Use either cup or ramekin (3 inch or 7.6cm in diameter) to press down into a round flat pancake about ½ inch in thickness.
Use a dough scraper and scrap up the cookie crust and place onto the dough. Shape it so the cookie crust hugs the bun. Avoid using your hand to cookie crust too much or else it will melt.
Use a bench scraper or dough cutter to cut a checkered shape.
Place the buns onto a baking sheet. Proof for another 30-45 minutes
preheat the oven to 350℉
Bake for 25-30 minutes or until golden brown.
Let it cool on cooling rack and enjoy!
Notes
If you want the checkered shape to be more distinct, add 10g more flour.