Whisk the agar agar powder and sugar together in a mixing bowl. Pour into a medium size sturdy pot and whisk in the water.
Whisk in the plant cream until combined, then switch to a silicon spatula. The vegan cream becomes foamy quickly and we don't want that for the panna cotta.
Place the pot over the smallest burner on a low heat. Allow the mixture to cook, stirring intermittently, for 10-15 minutes. If it hasn't come to a simmer after this point, turn the heat up just slightly. Cooking agar agar on a low and slow heat is key to getting the perfect set panna cotta the first time around, so don't rush it.
If the mixture hasn't come to a simmer after 20 minutes, turn the heat up again. Once bubbles start to appear on the surface, continue to cook for about 3-5 more minutes, stirring frequently. Add the vanilla and salt while you wait and stir to combine.
Pour the mixture into a large jug with a pouring lip - this makes it much easier to divide into your moulds. I use 80ml silicon muffin holes and it makes 8-9 panna cotta.
Pour the mixture into the moulds and allow it to cool before transferring to the fridge. To avoid a hardened base on your panna cotta, I recommend placing fully cooled panna cotta in a large airtight container. You can also lay cling film flush up against the base of each panna cotta, but this can get a bit finicky if you are using a silicon muffin tray.
Allow the cooled panna cotta to set for at least 3 hours or up to overnight. I like to make them the night before to correct any errors if they arise. If your panna cotta haven't set after 3 hours, you have not cooked the mixture long enough to gel it. The good news? You can decant the mixture back into the pot and cook it again to ensure it sets.