Combine the cream, milk, and sugar in a skillet over medium-low heat, stirring frequently.

In a small bowl, whisk the egg yolks with the salt.

When the cream mixture is hot but not boiling, gradually whisk about 3/4 cup into the egg yolks. Return the egg mixture to the saucepan and continue cooking and stirring until the custard reaches about 170 F to 175 F.

Place a mesh strainer over a bowl. Strain the hot custard mixture into the bowl and then whisk in the vanilla extract. Cover and refrigerate for at least 4 hours. Or set the bowl in an ice bath and keep replenishing the ice until the custard reaches 40 F.

Churn the custard mixture in an ice cream freezer following the manufacturer's instructions.

About 5 to 10 minutes before the ice cream is finished churning, prepare the chocolate. Melt the chocolate in a pan or heat-safe bowl over simmering water. Stir in the vegetable oil and let it cool a bit.

Slowly drizzle the slightly cooled chocolate into the churning ice cream. The chocolate will harden and break up into "chips" as it blends into the ice cream.

Pack the chocolate chip ice cream into a container and store in the freezer.