In a medium saucepan, combine the heavy cream, whole milk, brown sugar, vanilla extract, and salt. Heat over medium-low until hot but not boiling, about 5-7 minutes.

In a separate bowl, whisk egg yolks until pale. Gradually add a cup of warm cream mixture to the yolks, whisking constantly.

Return the mixture to the saucepan and cook, stirring constantly for 8-10 minutes until it thickens. Strain into a container, cool in an ice bath for 15 minutes, then refrigerate for at least 3-4 hours.

Melt butter in a skillet over medium heat until golden brown. Add pecans and toast for 2-3 minutes. Remove from heat and transfer pecans to cool.

Churn the chilled custard in your ice cream maker according to the manufacturer's instructions, about 20-25 minutes, then stir in toasted pecans.

Transfer the churned ice cream to an airtight container and freeze for at least 4 hours until firm.