Toast the Pecans: In a skillet over medium heat, toast the pecans for 5-7 minutes, stirring frequently, until golden and fragrant. Remove from heat and set aside to cool.
Prepare the Custard: In a medium saucepan, combine the heavy cream, whole milk, and granulated sugar. Heat over medium heat until the mixture begins to steam, but do not let it boil. In a separate bowl, whisk the egg yolks. Slowly add a small amount of the hot cream mixture to the egg yolks while whisking to temper them. Gradually add the rest of the hot cream mixture to the egg yolks and mix well. Cook the Custard: Return the mixture to the saucepan and cook over low heat, stirring constantly for 5-7 minutes, until the custard thickens and coats the back of a spoon.
Add Butter and Brown Sugar: Stir in the unsalted butter and brown sugar until the butter is fully melted and the sugar has dissolved. Add the vanilla extract and stir to combine. Remove from heat and let the mixture cool to room temperature. Chill the Custard: Transfer the custard to a clean bowl and cover with plastic wrap, pressing it directly onto the surface of the custard. Chill the custard in the refrigerator for at least 2-3 hours, or overnight for best results. Churn the Ice Cream: Pour the chilled custard into your ice cream maker and churn according to the manufacturer's instructions, typically for 20-30 minutes, until the ice cream reaches a soft-serve consistency.
Mix in the Pecans: Fold the toasted pecans into the ice cream using a spatula.
Freeze the Ice Cream: Transfer the ice cream to an airtight container, smooth the top, and freeze for at least 4 hours, or until firm.
Serve and Enjoy: Scoop and serve your homemade butter pecan ice cream, enjoying every creamy, crunchy bite!