In the bowl of a stand mixer, fitted with the whisk attachment, beat egg yolks, sugar, and salt on high speed until yolks lighten in color and thicken into a ribbon as you lift the whisk out of the bowl, about 2 minutes.

In a medium saucepan combine heavy cream and milk.

Heat over medium heat and bring to a simmer, about 5 minutes.

With mixer on low, gradually pour 1 cup of warm liquid into egg mixture.

Add egg mixture to saucepan.

Stir and and continue to cook over medium heat until mixture begins to bubble slightly and is thick enough to coat the back of a wooden spoon.

Immediately pour custard mixture through a fine mesh sieve over a bowl or large glass measuring cup.

Cover and chill the mixture thoroughly in the refrigerator.

Once the custard mixture is chilled, freeze in an ice cream maker, following the manufacturer's instructions.

While ice cream is churning, melt chocolate and oil together in the microwave, stirring every 30 seconds until completely smooth.

Transfer melted chocolate to a zip-top bag and seal well, pressing out as much air as possible. If necessary, place bag in a bowl of warm water to keep warm while the ice cream finishes churning.

Once ice cream reaches soft-serve consistency, about 1-2 minutes before being completely done, snip the very tip off the corner of the bag of chocolate.

Slowly drizzle most of the chocolate into the ice cream bowl as it churns, allowing the chocolate to swirl throughout.

Transfer ice cream to a freezer-safe container and drizzle the remaining chocolate on top.

Freeze 2 to 3 hours or overnight until firm.

Scoop and enjoy!