The ingredients.

Peel the skin of half a lemon, avoiding any white part (it would make the dessert bitter).

Place a saucepan on the stove with the milk and lemon peel pieces. Keep it on medium heat and turn off the heat just as it starts to boil, then set aside.

While the milk is heating, separate the egg yolks from the whites.

In a bowl, combine only the yolks (no whites), sugar, and cornstarch. Beat with an electric mixer on low speed until smooth.

Remove the lemon peel from the milk.

Pour the beaten mixture from the bowl into the saucepan.

Place on medium-low heat and get a wooden spoon ready to stir slowly.

When it starts to thicken, it's time to turn off the heat.

Transfer it to a mold and place this mold inside a larger pot with water (preheated, at least that's what I did).

Place in the oven at 340°F (170°C), with heat from above and below, preheated. This is called "baking in a water bath" for about 20 minutes.

Fresh out of the oven.

This is the cast iron kitchen tool for caramelizing the sugar.

Place the cast iron base directly on the stove until it's super hot.

Sprinkle sugar on top.

With the super hot cast iron base, press to caramelize the sugar.

This is how it turned out.

Place it in the fridge for at least an hour or until you're ready to serve.

Although ideally, it should be placed in separate containers with its caramelized sugar, I had to flip it out of the mold.