Preheat oven to 350°F.
Combine tahini, coconut sugar, egg, vanilla extract, baking soda, salt, and cinnamon (if using) in a bowl and whisk until smooth.
Fold in the chopped dark chocolate or chocolate chips.
Scoop dough onto a baking sheet lined with parchment paper, leaving plenty of room between cookies as they will spread.
Bake for 10-12 minutes.
Top with flaky salt and enjoy.
