Using 4 separate sealable containers, divide oats, milk, 1 cup of yogurt, honey, vanilla, and 1 teaspoon of cinnamon amongst all containers. (You can easily use just one sealable bowl as well and simply scoop out individually the next day).
Mix gently; cover and store in the refrigerator overnight, or up to 2-3 days.
In the morning, mix together the remaining 1 cup of yogurt and cinnamon. Place a dollop onto each serving of overnight oats and swirl in without completely mixing (just like the icing on a cinnamon roll).