First make the compote - put the washed blackberries in a small pan together with the date syrup/coconut sugar, vanilla and lemon juice. Gently heat it up and cook for about 10-15 minutes until you get a thick, sticky sauce.
Meanwhile, put the porridge in a saucepan and add the cinnamon. Mix together, then add the oat milk. Turn the heat on, and simmer over low heat for 10 minutes. It should be creamy, so add a little more milk, if needed. Turn off the heat, give it a stir, then put a lid on and rest for 5 minutes.
When the compote is ready, turn off the heat and rest.
Spoon the porridge into bowls, top with compote and scatter the seeds on top.
Serve warm.