In a medium saucepan, combine the heavy cream and whole milk over medium heat, stirring occasionally until you see small bubbles forming around the edges, about 5-6 minutes. Remove from heat once those bubbles appear!

In a separate bowl, whisk together egg yolks, granulated sugar, and brown sugar until the mixture becomes pale and creamy.

Slowly pour half of the hot cream mixture into the egg yolks while whisking constantly. Once blended, return this mixture to the saucepan over low heat, stirring gently until it thickens to 170°F, about 5-8 minutes.

Strain the mixture through a fine mesh strainer into a clean bowl. Stir in the vanilla extract and salt, cover tightly, and chill in the refrigerator for at least 4 hours.

In a skillet over medium heat, melt unsalted butter, then add the chopped pecans. Toast them for about 3-4 minutes, stirring frequently until golden and fragrant. Let them cool.

Pour the chilled custard into an ice cream maker and churn for about 20-25 minutes or until it reaches a soft-serve consistency. Add the toasted pecans before it's fully churned.

Transfer the churned ice cream into a freezer-safe container, cover tightly, and freeze for at least 4 hours until hardened.