My mom's flan is another classic. It's the easiest dessert to make and can be adjusted to any size. The only consideration is that it must be made a few hours in advance because it has to cool completely before serving.
The recipe below is for a "vanilla" flan, but you can make it "dulce de leche" flavor by simply replacing the sugar in the filling with dulce de leche. I'll call out the proportions.
The ingredient amounts are dictated by the size of the pan you choose to use. You can make it as small or as big as you want. For a 10" pan, I would use 12 eggs.
10-12 eggs
1 tablespoon of white sugar per egg (or half a tablespoon of dulce de leche per egg)
Plus approx 1/2 cup of white sugar for the caramel.
1 liter of whole milk. Here is why this recipe is easy: you don't have to be too specific about the quantities. 1 liter works for 10 or 12 eggs.
Splash of vanilla extract
Preheat the oven to 325°F.
Choose a metal pan that you can use on the stove and in the oven. Melt some sugar in it (just enough to cover the bottom) and coat the pan with the caramel. Yes, you do this on the stove. Set aside.
In a mixing bowl, mix the eggs and the sugar by hand. Add the vanilla extract and combine well. Gradually add the milk and mix until you have a homogeneous mixture. Pour into the metal pan coated in caramel.
Send to the oven for 1-1.25 hours. Let cool completely and refrigerate for at least 4 hours before serving. If you can leave overnight, even better!
For serving, flip the pan onto a not-too-shallow dish. The caramel will allow for an easy flip. If you are making a vanilla flan, you can always include a tablespoon of dulce de leche in each serving.