Flatten 120g chilled butter between greaseproof paper into an 8x15cm rectangle and refrigerate.
Mix 40g butter, flour, powdered milk, caster sugar, salt, and 150ml water in a mixer until combined.
Add yeast and mix for 5 minutes on low, then 7 minutes on medium speed.
Form dough into a ball and rest in a greased bowl for 15 minutes.
Microwave at 100W for six minutes then rest for 10 minutes to prove.
Roll dough into an 18x25cm rectangle and freeze on a lined sheet for 10 minutes.
Place chilled butter in the center of the dough and fold in thirds.
Roll to 1cm thickness, turn 90 degrees, repeat the fold and roll, then freeze for 15 minutes.
Repeat folding into quarters twice and freeze for another 15 minutes before refrigerating.
Mix sugars, almonds, zest, and extract with egg yolk to form six chilled balls.
Slice the apple thinly and toss in lemon juice.
Roll dough to 20x30cm, cut into six 10cm squares, and create the kite-fold borders.
Fill each square with almond paste and apple slices, sprinkle sugar, and prove for one hour.
Boil 25ml water, half the lemon juice, and sugar to create a thick syrup glaze.
Preheat oven to 220°C.
Brush pastry edges with egg and bake for 8-10 minutes until golden.
Glaze while warm and allow to cool on a wire rack.
Mix icing sugar with lemon juice and drizzle over cooled pastries.