For visual step-by-step instructions, refer to the photos in the post.

Make the filling:

• Combine finely chopped candied wintermelon, sesame seeds, shredded coconut, cooked glutinous rice flour (koh fun), coconut oil and water together in a bowl. Mix together.
• Divide the filling into 8 balls, about 28g each.

Make the Water Dough:

• Mix together cake flour, lard and water in a small bowl.
• Divide into 8 portions about 23g each. Cover and let it rest for 30 minutes at room temperature.

Make the Oil Dough:

• In a separate bowl, mix together cake flour and lard.
• Divide into 8 portions about 16g each. Cover and let rest for 30 minutes at room temperature.

Assemble:

• Preheat oven to 400°F/204°C. Line a large baking tray with parchment paper.
• Roll out the Water Dough into a round disc. Place 1 ball of Oil Dough in the centre of the water dough and gather the seams to enclose.
• Flatten dough into an oval/oblong shape with a rolling pin.
• Coil up the dough (jelly roll style). Repeat with the remaining dough, cover and let it rest for 20-30 minutes.
• After resting, rotate the coiled dough 90 degrees, flatten with a rolling pin and coil it up again (jelly roll style) to build up the flaky layers and let it rest for another 20 minutes.
• Push down the centre of the dough (seam-side up) with one thumb and pinch the two ends up together with the other thumb and forefinger.
• Flatten the dough with your palm.
• Roll out the dough with a rolling pin.
• Place the wintermelon filling in the centre of the dough and gather up the seams to enclose.
• Gently flatten the dough into a large disc using a rolling pin. Be careful not to puncture the dough.
• Make 2 parallel slits on the top of the disc.
• Combine the egg yolk and water to make an egg wash. Lightly brush the tops with egg yolk wash and sprinkle some sesame seeds (optional). Repeat with the remainder.
• Bake at 400°F/204°C for 20-25 minutes until golden brown and flaky.
• Remove from oven and cool on a rack.