Add the oat milk and agar agar into a saucepan. Turn on the heat, whisk well to dissolve and bring to a gentle boil. Allow to simmer for 2 minutes, whisking often.
Add in the remaining ingredients and whisk well to dissolve the sugar and pistachio spread.
Pour the mixture into small moulds (or individual glasses) and refrigerate for minimum 1 hour or until set.
When ready to serve, remove from moulds, top with crushed pistachios and fresh berries. Enjoy.