Instructions:

1. Prepare the Base:
   In a medium saucepan, combine the heavy cream, milk, and brown sugar. Heat over medium heat, stirring until the sugar is dissolved and the mixture is steaming (don’t boil).

2. Temper the Egg Yolks:
   Whisk the egg yolks until smooth in a separate bowl. Gradually add about 1/2 cup of the hot cream mixture to the yolks while whisking constantly to temper them.

3. Combine and Cook:
   Slowly pour the tempered yolks back into the saucepan, whisking continuously. Cook over low heat, stirring with a wooden spoon until the mixture thickens and coats the back of the spoon (about 170°F to 175°F).

4. Flavor and Strain:
   Remove from heat and stir in cinnamon and vanilla extract. Strain the custard through a fine-mesh sieve into a clean bowl to remove any cooked egg bits.

5. Chill the Custard:
   Cover with plastic wrap, pressing it onto the surface to prevent a skin from forming. Refrigerate for at least 4 hours or overnight.

6. Churn the Ice Cream:
   Once chilled, churn the custard in an ice cream maker according to the manufacturer’s instructions. Transfer to a lidded container and freeze for 2–3 hours before serving.