Steps

1. Line a 15cm x 15cm mold with parchment paper. Cut the paper a bit larger than the mold, place it in the center to create creases, make deep cuts in four places, and layer them by folding alternately. Trim any excess paper sticking out.
2. In a bowl, combine brown sugar (80g) and milk (100ml) and mix well.
3. Heat the bowl with brown sugar and milk in a microwave (600W) for 1 minute, then stir again to dissolve the brown sugar. If there are any undissolved lumps, strain through a sieve and crush to dissolve completely. It's okay if a few small lumps remain.
4. In a separate bowl, crack 1 egg and beat it.
5. Add 1 tbsp vegetable oil to the beaten egg and mix thoroughly to prevent separation. Adding oil makes the batter moist.
6. Add the dissolved brown sugar and milk mixture to the egg and oil bowl, and mix well.
7. Sift in 150g pancake mix. Gently mix until just combined, being careful not to overmix. Sifting helps prevent lumps.
8. Pour the batter into the prepared mold and tap it down twice from a height to remove air bubbles.
9. Scatter 20g raisins evenly over the top of the batter.
10. Pour about 2cm of water into a deep frying pan and bring it to a boil.
11. Once boiling, turn off the heat momentarily. Place a steaming rack (or heatproof dish) in the frying pan. Carefully place the mold on top of the rack.
12. Turn the heat back to medium-low, cover with a lid, and steam for 20 minutes. If the water level gets low during steaming, open the lid, add more water, and continue steaming.
13. After 20 minutes, turn off the heat and open the lid. Insert a bamboo skewer into the tallest part of the bun. If it comes out clean, it's done. If raw batter sticks, steam for a few more minutes.
14. Carefully remove the steamed bun from the mold, being mindful of the heat. Let it cool slightly. Cover loosely with paper to prevent the surface from drying out.
15. Once slightly cooled, remove the parchment paper. Cut diagonally to form triangles. You can cut them into any shape you prefer, such as squares.