In a small saucepan, over medium-low heat, stir together the heavy cream, milk, vanilla and the sugar (minus 4 tablespoons of sugar which will be mixed with the egg yolks). Heat the mixture over medium-low heat until hot, but not bubbling. Don’t let it boil. As soon as you see small bubbles around the perimeter of the saucepan, the milk is warm enough and ready.

In a medium bowl, whisk the egg yolks, the 4 tablespoons of sugar and the salt until well combined. While stirring, slowly add a cup of the hot cream mixture to the yolk mixture making sure you keep whisking vigorously to prevent the yolks from curdling.

Next, stir in the yolk mixture into the saucepan. Cook over medium-low heat, stirring often, until the mixture is thick enough to coat the back of a spoon, about 10 minutes.

Strain the mixture through a fine mesh strainer. Cover and place in the refrigerator to cool.

Place the raspberries and sugar in a blender and process until smooth. If the raspberries are not very sweet, you can add additional sugar if desired. Strain the mixture through a sieve to remove the raspberry seeds.

Pour the pureed raspberry mixture into the ice cream base and stir to combine. Cover and chill for at least 4 hours or overnight.

Pour the the raspberry custard into an ice cream maker. Churn according to manufacturer’s instructions until it reaches the consistency of soft-serve ice cream.

Transfer to a freezer-safe container and freeze for about 4 hours before serving.