In a saucepan, heat 500 ml of whole milk and 250 ml of heavy cream over medium heat until it reaches a simmer.
In a separate bowl, whisk together 200 grams of granulated sugar and 6 egg yolks until the mixture becomes pale and thick.
Slowly pour the hot milk mixture into the egg yolk mixture, whisking continuously to avoid curdling the eggs.
Pour the combined mixture back into the saucepan and cook over low heat, stirring constantly, until it reaches a custard-like consistency and coats the back of a spoon.
Remove the saucepan from heat and let the custard cool to room temperature. Then, cover and refrigerate for at least 4 hours or overnight.
Once the custard is chilled, add 1 teaspoon of pure vanilla extract and any desired flavorings (such as fruit puree, chocolate, or nuts) to the mixture.
Pour the mixture into an ice cream maker and churn according to the manufacturer's instructions.
Transfer the churned gelato to an airtight container and freeze for at least 2 hours before serving.