Step 1: Heat the Milk and Cream : In a medium saucepan, combine the milk, heavy cream, and half of the sugar. Heat gently over medium heat until warm but not boiling. Stir occasionally.

Step 2: Whisk the Egg Yolks : In a separate bowl, whisk together the egg yolks and remaining sugar until pale and thick. Gradually pour in a bit of the hot milk mixture while whisking constantly to temper the eggs.

Step 3: Cook the Custard : Pour the tempered yolks back into the saucepan and cook on low heat. Stir continuously until the mixture thickens and coats the back of a spoon (170–175°F / 77–80°C). Do not boil. Remove from heat once thickened.

Step 4: Add Peanut Butter and Vanilla : Whisk in the peanut butter, vanilla extract, and a pinch of salt until smooth and creamy. Strain the custard through a fine-mesh sieve into a clean bowl. Cover with plastic wrap (pressed onto the surface) and refrigerate for at least 4 hours or until completely chilled.

Step 5: Make the Chocolate Swirl : In a small saucepan, melt chocolate chips, butter, and corn syrup together over low heat. Stir until smooth and glossy. Set aside to cool slightly — it should be pourable but not hot.

Step 6: Churn the Ice Cream : Once chilled, pour the custard into your ice cream maker and churn according to manufacturer’s instructions (usually 20–25 minutes).

Step 7: Add the Chocolate Swirls : When the ice cream is almost done churning, drizzle in the cooled chocolate sauce in thin streams. The chocolate will create ribbons as it freezes. Alternatively, you can layer the ice cream and chocolate sauce in a container and gently swirl with a knife.

Step 8: Freeze Until Firm : Transfer the ice cream to a lidded container. Freeze for at least 2–3 hours before serving for a firm texture.