Heat 1 cup sugar in a small saucepan over medium heat, stirring with a spoon to heat sugar evenly, until it starts to melt, then stop stirring and simmer, until it is golden caramel.
Slowly add 1 cup of cream (mixture can spatter) and cook, stirring, until all of caramel has dissolved. Transfer to a bowl and stir in sea salt and vanilla. Cool to room temperature.
Meanwhile, bring milk and remaining cup cream, just to a boil in a small heavy sauce pan, stirring occasionally.
Lightly whisk yolks in a medium bowl until frothy, then add half of hot milk mixture in a slow stream, whisking constantly.
Pour back into saucepan and cook over medium heat, stirring constantly with a wooden spoon, until the custard thickens and coats the back of the spoon (do not let boil). Remove from the heat.
Stir in cooled caramel mixture.
Cool custard, stirring occasionally, in an ice bath and cool down to 5-10˚C.
Set time to 30 minutes and press power button on.
Pour mixture into chute.
Either eat immediately or transfer to an airtight container and freeze for 1-2 hours for a firmer texture.