Cut a lemon in half, squeeze the juice over it an stir it in. Cuts out the sweetness, but adds a nice tartness to the apple.

[He usually did that for himself- it still left a bit of sweetness to help the cinnamon not be overwhelming, but it also made it... not so sweet. A good balance.

He did gesture to one of the bowls that had fruits, some being lemons, there in it.]