1. Using a pastry brush, lightly grease a square pan with a small amount of oil. Set the pan aside on a flat surface.

2. Break the agar agar into small pieces using your hands and place them in a medium-sized saucepan. Add the water and mix well with a wooden spoon. Let it sit for 10 minutes.

3. In a separate saucepan, combine the milk and condensed milk. Use a whisk to thoroughly mix the ingredients until well combined.

4. Place the saucepan with the agar agar mixture on the stove over low heat. Stir occasionally with a silicone spatula until the agar agar is completely melted.

5. Carefully pour the melted agar agar mixture into the saucepan with the milk mixture. Heat gently over low heat while whisking continuously to ensure the mixture becomes hot and well combined.

6. Add the vanilla essence to the mixture and stir thoroughly with a wooden spoon to incorporate it evenly.

7. Pour the mixture into the prepared square pan using a silicone spatula to scrape out any remaining mixture from the saucepan. Allow it to cool at room temperature, then place it in the refrigerator for 3 to 4 hours to set.

8. Once set, invert the pan onto a cutting board and use a sharp chef’s knife to cut the dessert into even pieces.

9. Serve the dessert on a plate or in a serving dish.