Chop the dark chocolate into small, even pieces for faster melting. Place the chocolate and coconut oil together in a microwave-safe bowl and heat in 20-second intervals, stirring between each interval, until completely melted and smooth. Set aside to cool slightly—it should still be pourable but not piping hot. I use Lindt 70% cocoa bars because they have a rich snap and don't burn easily, but any quality dark chocolate works here.

Add the rolled oats, milk, frozen blueberries, yogurt, vanilla essence, maple syrup, salt, and ground cinnamon to a blender in that order. Blend on high speed until the mixture is completely smooth and creamy, about 60-90 seconds. The frozen blueberries will break down and give the mixture a beautiful purple hue and subtle berry flavor throughout. For a creamier result, I always use Fage 5% yogurt—it has a much richer texture than regular yogurt.

Divide the fresh blueberries evenly among 4 mason jars or similar containers (about 1/4 cup per jar). Pour the blended oat mixture from Step 2 over the fresh blueberries, filling each jar about three-quarters full. Give each jar a gentle stir to distribute the berries and combine the layers slightly.

Drizzle the cooled melted chocolate from Step 1 evenly over the top of each jar, creating a thin chocolate layer. You can use a spoon or squeeze bottle for even distribution. Cover the jars with lids and refrigerate for at least 1.5 hours, though overnight (8-12 hours) is ideal as it allows the oats to fully hydrate and the flavors to meld together beautifully.

Remove the jars from the refrigerator and serve cold. The oats should be creamy and spoonable with a thick, pudding-like consistency. You can eat straight from the jar or transfer to a bowl. If the mixture has thickened too much, stir in a splash of milk to reach your preferred consistency.