In a heavy-bottomed saucepan, heat 200 grams of sugar over medium heat. Stir continuously until the sugar melts and turns into a golden-brown caramel. Remove from heat and let it cool slightly.
In another saucepan, heat 500 ml of full-fat milk until it reaches a simmer. Remove from heat.
In a separate bowl, whisk together 4 egg yolks and 100 grams of sugar until the mixture is pale and creamy.
Slowly pour the warm milk into the egg yolk mixture, whisking continuously to avoid curdling. Once combined, pour the mixture back into the saucepan.
Cook the custard mixture over low heat, stirring constantly, until it thickens enough to coat the back of a spoon. Remove from heat and let it cool.
Stir the caramel into the cooled custard mixture until well combined.
In a separate bowl, whip 250 ml of heavy cream until soft peaks form. Gently fold the whipped cream into the caramel custard mixture.
Pour the mixture into an ice cream maker and churn according to the manufacturer's instructions. If you don't have an ice cream maker, pour the mixture into a container and freeze for 4-6 hours, stirring every hour to break up ice crystals.
Once the ice cream reaches the desired consistency, transfer it to an airtight container and freeze for at least 2 hours before serving.