In a sauce pan over medium heat, bring to boil the milk, sugar, lemon and the cinnamon.
In a medium bowl whisk the 4 eggs.
Once the milk mixture starts to boil, remove the lemon and the cinnamon and turn the heat off.
Add 1/2 cup of the milk mixture to the beaten eggs. Whisk wish wish!! When the eggs are fully incorporated, pour the mixture back to the sauce pan and whisk.
Strain the mixture into a bowl. (OPTIONAL: Use a hand blender to blend it up).
Pour the mixture into each ramekin (or into one big mold).
Fill half of a baking dish with water, add the ramekins and then place in the oven, being careful not to get any water in the flan.
Cook in the oven for approximately 35 to 40 minutes. The center should be firm, but soft, and not liquid.
Remove the ramekins from the baking dish.
Cool in the fridge, for at least 1 hour or overnight.
Serve cold and enjoy! Bon profit!