Cambodian Palm Sugar and Coconut Milk Jelly (Bok L'hong)

In a medium saucepan, combine the palm sugar and 1/2 cup of water. Cook over medium heat, stirring constantly, until the palm sugar is fully dissolved and the mixture is smooth, about 5-7 minutes. Strain the palm sugar syrup through a fine-mesh sieve to remove any impurities and set aside.

In a separate saucepan, whisk together the coconut milk, agar-agar powder, and salt. Bring the mixture to a gentle boil over medium heat, stirring continuously to prevent sticking, about 5-8 minutes. Reduce heat to low and simmer for 2 minutes, ensuring the agar-agar is fully dissolved.

Pour half of the coconut milk mixture into a separate bowl. Stir the strained palm sugar syrup and vanilla extract (if using) into the remaining coconut milk mixture in the saucepan. Mix well.

Pour the palm sugar coconut milk mixture into a 9x5 inch loaf pan or individual molds. Let it set at room temperature for 10-15 minutes until a thin skin forms and it is slightly firm to the touch.

Gently pour the plain coconut milk mixture over the partially set palm sugar layer. Place the pan or molds in the refrigerator and chill for at least 2-3 hours, or until completely firm.

Once set, carefully unmold the jelly onto a cutting board. Slice into desired shapes and serve chilled.