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Mix all the ingredients except the egg yolks together in a pan. Heat the mixture over medium heat. Whisk the egg yolks together in a medium-sized bowl. Pour the cream into the egg yolks. Pour the mixture back into the pan and heat it over medium heat. Let the custard thicken. Serve.
Mix 3 cups of milk, 3 tbsp. of cornstarch, teaspoon of salt, cup (100 g.) of sugar, 2 tbsp. of butter, and a pinch of vanilla extract together in a pan. Mix the ingredients together until they've blended well. Heat the ingredients until they're reached a simmer. Then, remove them from the heat. Whisk the 4 egg yolks together until they turn pale. This should take about 1 minute. Pour the cream into the egg yolk and continue to whisk the yolks as you do this. This will heat the yolks gently without cooking them. Stir it constantly with a wooden spoon as it continues to heat up. Take care to scrape the bottom of the pan with the spoon so the custard doesn't stick. Cook until the custard thickens to the desired consistency. Do not allow the custard to boil -- this will curdle it leaving you with a lumpy mess. Wait at least five minutes for the ingredients of the custard to thicken a bit. Sprinkle a pinch of cinnamon and a handful of berries over the custard and enjoy this rich and creamy dessert.