In a large saucepan, combine the milk and vanilla. Place over medium heat and bring to a simmer.
Meanwhile, in a large bowl, beat the egg yolks with a whisk until thickened and the color has turned from bright yellow to pale yellow. Incorporate the evaporated milk, sugar and cornstarch, whisk until cornstarch has dissolved and the mixture is smooth and combined.
After about 15 minutes, the milk will begin to form a thin film on top (called nata) and start to come to a simmer. Remove from the heat at this point.
To temper the egg yolk mixture, constantly whisk the egg mixture while adding the hot milk into the bowl one ladle full at a time. Then return it all into the saucepan and set over medium heat. Continue to cook for about 10 to 12 minutes, stirring constantly with a spatula or whisk and making sure mixture doesn’t stick to sides or bottom of the pot, until it has thickened to the consistency of a very thin pudding.
Remove from the heat. Ladle into ramekins and sprinkle cinnamon on top. You can serve it at room temperature or let cool, cover with plastic wrap, place in the refrigerator and serve chilled. Garnish with fresh berries.