Place the can of unsweetened condensed milk in the freezer for 2 to 5 hours. It should be very cold, almost frozen. Once ready, start preparing your ice cream. If it becomes too hard, leave it at room temperature for a few minutes.
Prepare the egg and sugar mixture: beat the egg yolks with the sugar for at least 10 minutes. The mixture should become pale, smooth, and very frothy.
If you're making plain vanilla ice cream, add the seeds from the vanilla bean at this stage and whisk them into the mixture.
Whip the very cold heavy cream until firm, then set aside in the refrigerator.
Beat the chilled condensed milk for at least 10 minutes until it triples in volume and becomes smooth and airy.
Whip the egg whites until stiff peaks form.
Incorporate the egg yolk mixture into the beaten condensed milk, whisking briefly until well combined.
Then, fold this mixture into the whipped cream in several additions, using a whisk.
Finally, gently fold in the stiff egg whites in 3 or 4 additions, always using a whisk to keep the texture light and smooth.
Your no-churn ice cream is now ready!
You can divide it into several portions and customize each one with your favorite mix-ins: crushed Oreos, melted chocolate, caramel swirls, chopped Snickers, Daim pieces, Kinder Bueno bits, etc. (see suggested variations above).