1. Prepare the Vanilla Bean (if using):
   • If using a vanilla bean, split it lengthwise and scrape out the seeds using the back of a knife.
   • In a saucepan, combine the heavy cream, milk, sugar, vanilla bean seeds, and the scraped vanilla bean pod. Heat the mixture over medium heat until it’s just about to boil. Remove from heat and let it steep for about 15-20 minutes to infuse the vanilla flavor.
2. Make the Custard Base:
   • In a mixing bowl, whisk the egg yolks until they become slightly lighter in color.
   • Gradually pour the warm vanilla-infused cream mixture into the egg yolks, whisking continuously to prevent curdling.
3. Combine and Cook:
   • Pour the mixture back into the saucepan and cook over low to medium heat, stirring constantly, until the custard thickens enough to coat the back of a spoon. This usually takes about 5-7 minutes.
4. Strain and Cool:
   • Remove the vanilla bean pod (if used) and strain the sauce through a fine-mesh sieve into a clean bowl to remove any cooked egg bits.
   • Allow the sauce to cool to room temperature.
5. Optional: Add Vanilla Extract:
   • If you didn’t use a vanilla bean, you can add pure vanilla extract at this point for an extra boost of flavor. Start with 1-2 teaspoons, depending on your preference.
6. Serve:
   • Once cooled, the vanilla sauce is ready to be served. Pour it over slices of bread pudding just before serving.

Enjoy your homemade vanilla sauce with bread pudding!