Gather the ingredients.

Combine the cream, milk, and sugar in a medium heavy-duty saucepan.

Heat over medium-low heat, stirring frequently, until the sugar is dissolved and the mixture is hot.

Pour about 1 cup of the hot mixture into the beaten egg yolks, whisking constantly. (This is called tempering.)

Pour the egg mixture back into the saucepan, whisking constantly.

Cook over medium heat, stirring constantly until the hot mixture is slightly thickened and coats the back of a spoon, about 6 minutes. Do not let the mixture boil.

Strain through a mesh strainer into a bowl and stir in the vanilla.

Cover and refrigerate until completely cold, about 1 hour. Churn according to your ice cream maker's instructions. Freeze while you make the peanut butter sauce.

Gather the ingredients for the peanut butter sauce.

Combine the peanut butter, whipping cream, light corn syrup, and brown sugar in a medium saucepan. Heat over low heat, stirring until the sugar is dissolved and the mixture is smooth.

Transfer to a bowl and chill thoroughly.

Transfer the finished ice cream to a rectangular container. Dollop 3 to 4 large spoonfuls of the peanut butter sauce evenly over the ice cream.

Swirl the peanut butter through the ice cream lightly with a knife to create ribbons. Cover and freeze until the mixture is solid, about 1 hour.

Serve in cones or cups; offer some warmed extra peanut butter sauce to use as a topping, if desired.