First, prepare the beans (start the night before). I wash my red mung beans until the water runs clear, then soak them in plenty of cold water for 4-6 hours or overnight. This ensures even cooking. Never skip this step!

After soaking, I drain and rinse the beans, then cook them in 8 cups of fresh water. I bring to a boil, then simmer for 30-40 minutes until they're easily squished between my fingers. Then I drain completely.

I return the cooked beans to the pot with vegetable oil, sugar, and salt. Then I cook over medium-low heat, stirring constantly for 15-20 minutes until it's very thick. I know it's ready when I can draw a line through it with my spoon and the line stays clear. I let this cool completely for about an hour.

I prepare my dough. I mix flour and salt, then work in room temperature lard with my fingertips until it looks like sand. I slowly add room temperature water while mixing, then knead gently for 3-4 minutes until smooth. I cover and let it rest for 30 minutes.

I preheat my oven to 350°F (180°C), line baking sheets with parchment, and mix my egg wash ingredients in a small bowl.

I divide both the cooled filling and dough into 20 equal portions, rolling the filling into balls and keeping the dough covered while I work.

I roll each piece of dough into a thin 4-inch circle, place a ball of filling in the center, then carefully bring the edges up and seal completely without gaps.

I then create the patterns. I dust my mooncake mold with flour, place the filled dough sealed-side down, press firmly, then tap to release. I place them pattern-side up on my baking sheet with 2 inches between each.

I bake for 15 minutes, then let them cool for 5 minutes before brushing with egg wash. Back in the oven for another 8-10 minutes until they're beautifully golden brown. I let them cool completely for at least an hour before moving them.

Serve and enjoy your hopiang hapon!