In a large skillet over medium heat add the pecans and butter. Cook the pecans until lightly browned and fragrant. Stir the pecans often to avoid burning. Remove the pecans from the skillet and allow to cool.
Prepare a large bowl of ice and set aside.
In a saucepan over medium heat, add the half and half and brown sugar, Stir constantly until the temperature reaches 175 degrees. Remove the saucepan from the heat.
Slowly add about 3 tablespoons of the hot half and half to the eggs, stirring constantly, to temper the eggs.
Then, add the eggs to the saucepan and heat, stirring continuously, until the temperature reaches 160 degrees.
Remove the saucepan from the heat and set in the bowl of ice to stop the cooking. Allow the mixture to cool for 2 minutes, stirring constantly.
Stir in the whipping cream and vanilla until completely combined.
Transfer the mixture to a container and press plastic wrap down across the top, touching the ice cream mixture. Refrigerate for at least 2 hours to overnight.
Pour into your ice cream maker and allow to churn for 20-30 minutes (or following manufacturer's instructions for your ice cream maker) During the last 5 minutes of the freezing cycle, add the pecans.
Transfer the ice cream to an airtight freezer container and freeze until solid.