Cut the pumpkin into 2cm slices, remove the peel, and dice into 2cm cubes. Place the pumpkin and 1 tbsp of water in a microwave-safe container, cover loosely with plastic wrap, and microwave at 600W for 4-5 minutes.

Place a fine mesh strainer or sieve over a bowl. Press the cooked pumpkin through the mesh using a spatula to create a smooth puree.

In a pot, combine water and agar powder. Heat over medium heat until boiling, then reduce to low heat and stir for 1 minute. Add sugar and milk, stirring until the sugar dissolves.

Remove from heat and mix in the pumpkin puree until smooth.