Heat the milk and cream in a saucepan on the stove.
Halve the vanilla pod and use the sharp blade of a knife to scrape out the seeds.
Add both the seeds and the pod to the saucepan, as well as the yellow part of the lemon peel.
Be careful not to boil the milk. Separately, in a bowl, beat the egg yolks with the sugar for 3 or 4 minutes.
Once the mixture in the saucepan it is hot and well mixed, gradually begin to incorporate the egg and sugar mixture while continuing to whisk constantly.
Cook over low heat or pour the pan contents into a bowl and cook in a bain marie, stirring constantly.
Cook until the cream forms ribbons when you dip a spatula into it. If you have a food thermometer, check to make sure that you have brought the cream up to 181°F (83°C).
Be careful not to let the cream boil or it may form lumps. Once ready, pass the cream through a sieve to remove any lumps, then transfer to a bowl and immediately dip it in a pot full of ice to cool.
If you want you can thicken the cream further, add one teaspoon of cornstarch and mix thoroughly, but remember that once in a refrigerator, the cream will thicken further on its own.
Once the cream has reached your desired consistency, keep it in the refrigerator for up to 2 or 3 days.