In your preferred jar, (16-ounce jars are a good size for this recipe) mix together your oats, chia seeds, and flax seeds with your milk, cold brew, vanilla extract, and maple syrup. Cover and place in the fridge overnight or at least for 4 hours.
In a separate bowl, mix together Greek yogurt, pumpkin puree, heavy cream, maple syrup, and pumpkin pie spice. Cover and store in the fridge until you are ready to eat.
In the morning, take both the oatmeal jar and the bowl of pumpkin topping out of the fridge. Spoon Greek yogurt topping over oatmeal and enjoy!