I start by washing my apple and cutting it into small, bite-size pieces. I leave the skin on since it softens nicely overnight and adds a bit of extra fiber. Keeping the pieces small helps them blend into every bite of oats instead of sinking to the bottom of the jar.
Next, I add the rolled oats, apple cider, milk, brown sugar, and cinnamon straight into my jar with the diced apple. I don't bother dirtying a separate bowl since everything ends up in the same container anyway. This step takes me about two minutes.
Once everything is in the jar, I put the lid on and give it a good shake, or I stir it well with a spoon if I'm using a bowl instead. I make sure the cinnamon doesn't clump at the bottom, since that's an easy spot for it to hide.
I pop the lid on tight and slide the jar into the fridge before I go to bed. The oats need at least six to eight hours to soften and soak up all that apple cider flavor, so I try not to peek until morning.
In the morning, I pull my jar straight out of the fridge and eat it cold, no reheating required. If I'm in a rush, I just grab it and head out the door, and if I have a few extra minutes, I'll add toppings before digging in.