Place the blackberries in a bowl. Mash with a fork. Add the sweetener. Stir to combine. Add the ½ teaspoon chia seeds. Stir to combine. Set aside.
In a food processor or blender, add the banana pudding ingredients. Pulse until smooth. For a more smooth pudding, let it sit for 5 minutes and then pulse again to break up the chia seeds. Pour into a lidded container.
Cover and refrigerate the pudding and toppings at least 45 minutes or overnight. It will thicken more the longer it sits, so if you prefer a firmer pudding, refrigerate overnight.
When you're ready to serve, pour equal amounts into two serving dishes. Top with equal amounts of blackberry sauce. Add almond slivers, granola or coconut flakes for garnish.
* For sweetener, I prefer maple syrup, agave, or a zero-calorie sweetener like stevia.