Bring the almond milk, sugar and vanilla beans and pod to a simmer over low heat for 5 minutes. Remove the pod and keep the milk warm while you prepare the risotto.
Heat the butter in a large saucepan over medium heat. Add the rice and stir with a wooden spoon to coat evenly with the butter. Lower the heat to medium low and begin adding the milk 1 cup at a time, stirring often and allowing each addition of milk to be absorbed before adding the next. Be sure to run the spoon along the bottom of the pan to ensure the risotto doesn't stick or burn. Cook until the rice is tender but still firm, about 20 minutes. Remove from the heat and stir in the white chocolate and salt.
Serve warm, garnished with the blackberries and a sprinkling of grated dark chocolate.