• All ingredients ready? Let's begin!
  
• Set the butter out to reach room temperature.

To make the munggo:

• Place the beans in a large bowl and cover with several inches of cold water. Cover and leave to soak overnight.
  
• The next day, drain the old water and transfer the beans to a pot. Fill the pot with water to rest a few inches above the beans.
  
• Bring the water to a boil over high heat. Reduce heat to medium and continue cooking until the water evaporates to rest slightly above the beans (about 30 minutes or more).
• Put the sugar into the pot and stir. Continue cooking until it becomes thick and most if not all of the liquid has been absorbed by the beans, up to an hour.
  
• Transfer the contents of the pot to a high-powered blender or food processor and pulse to mix until you have a smooth puree.
  
• Use a spatula to move the paste back into the pot and put over medium low heat.
• Add the sweetened condensed milk and the flour. Stir with a spatula or wooden spoon for 30 minutes or until the puree thickens into a heavy paste.
  
• Remove from heat and allow to cool completely. You can put it in the fridge to speed up this process.

To make the ube filling:

• Heat a large skillet over medium heat and add the butter.
  
• Once the butter has melted, add the ube and coconut milk.
  
• Turn the heat up to high until it begins to boil then reduce back to medium.
  
• Stir every few minutes for 15 minutes or until the ube is soft enough to pierce through easily with a fork.
  
• Transfer the contents of the skillet to a high-powered blender or food processor and pulse until thick and smooth.
  
• Transfer the puree back to the skillet and place over medium-low heat. Add the sweetened condensed milk, evaporated milk, and sugar.
  
• Stir to combine and allow the puree to simmer for 30 minutes, stirring occasionally. The puree should become very thick and stodgy.
  
• Remove from heat and allow to cool completely. You can speed up the process in the fridge if you want.
  

For the pastry:

• Preheat oven to 350F and line a large baking tray with parchment paper.
• In a large bowl, add ¼ cup of hot water and 1 tablespoon of sugar. Mix to dissolve the sugar. Add 1 cup of flour and the salt. Cut ¼ cup of butter into the bowl too.
  
• Mix using your hands until the butter is well distributed and the dough forms a ball. If it is too dry, you can add a little bit of water. Roll into a ball and then cover with a clean towel.
  
• In a separate bowl, add the remaining flour and cut in the remaining butter. Mix with your hands until it forms a dough.
  
• Lightly flour a clean surface and roll out the bigger dough to a half inch thickness in a rectangle shape.
  
• Separately, roll out the second dough to a rectangle 2/3rds the size of the first. Place it on one side of the larger dough.
  
• Fold the opposite end of the first dough 1/3rd of the way over, then fold the other edge over similarly (like a letter).
  
• Turn the dough so the long end is facing you and roll it back out. Fold into thirds again. Allow the dough to rest for 10 minutes.
  
• Roll the dough into a triangle again then cut it in half long ways.
• Roll up each half long ways like a hotdog. Cut each dough roll into 12 even chunks. Cover them while you work to prevent them dying out.
  
• Flatten a dough piece into a thin circle.
  
• Add a tablespoon of your chosen (cooled) filling into the center. Fold all the edges of the dough over to meet in the middle then pinch closed.
  
• Place the dough ball in a biscuit cutter and press down to get the dough to seal and shape.
  
• Place the circle onto the baking tray, pinched side up, and repeat with remaining dough.
  
• Bake for 15-20 minutes. They should turn golden on top.
• While the hopia is baking, crack an egg into a bowl with a little bit of water and beat with a fork.
  
• Remove the hopia from the oven and turn over. Brush the top with the egg wash and return to the oven for another 10 minutes until lightly browned.
  
• Remove from oven and cool before serving.