Combine bread flour, sugar, salt and instant yeast in a mixing bowl. (Bowl A)
Warm milk and butter in a saucepan over low heat until butter mostly melted. Remove from heat. If mixture is too hot, allow to cool to lukewarm around 35C to 40C. Add the egg and whisk to combine. (Bowl B)
Combine Bowl B into Bowl A. Mix with a spatula until all the flour are incorporated. Transfer dough onto work surface. Dough will be sticky at first but as you knead, the dough will come together and become less sticky when gluten develops.
Knead for about 10 minutes until dough is smooth and not sticking to your hands anymore. When you stretch a small piece of dough with fingers, it should not break easily. Round into a ball. Transfer to bowl and cover. Allow to rise to double the size. About 60 minutes.
Once dough has risen, gently punch to release gas. Divide into 6 equal portions. Round into balls and allow to rest for 10 minutes.
Place onto a baking tray lined with parchment paper, spacing out evenly. Flatten the dough into roughly 9cm round. Cover and allow to rise the 2nd time for about 30 minutes. At this point you can start preheating your oven to 190C.
Meanwhile, prepare a bowl of water with a splash of lemon juice. Cut apples into quarters and remove the core. Slice each quarter as thinly as possible. Place sliced apples into the lemon water to prevent oxidation. When ready to use, remove apples and dry them with kitchen paper. Divide into 6 portions and arrange them together like a fan.Note: I used about a quarter apple for each bun. So technically you only need 1.5 apples.
Take out bay leaf custard from the refrigerator and whisk to loosen and smooth out the custard. Spoon about 1 tsp of custard onto the center of each buns. Place sliced apples over the custard on the buns. Brush a light egg wash around the sides of the buns that are not covered by the apples. Send to bake for about 8 mins or until the buns are golden brown.
While buns are baking, slice 6 thin wedges of camembert. Get ready some melted butter. Once buns are out from the oven, immediately brush melted butter all over the buns and over the apples. Place one wedge of camembert on each bun. Allow to cool before eating.