To make the ice cream base, melt the butter in a medium saucepan over medium heat. Stir in the brown sugar and salt. Whisk in 1 cup of the cream and all of the milk. Continue to stir occasionally until warm.
Pour the remaining 1 cup cream into a large bowl and set a large mesh strainer on top.
In another bowl, whisk the egg yolks. Slowly pour the warm brown sugar mixture into the egg yolks, whisking constantly, then pour the warmed egg yolks back into the saucepan.
Stir the mixture with a rubber scraper constantly over medium heat, being sure to scrape the bottom as you stir. Once the mixture thickens and coats the back of the scraper, pour it through the strainer and stir into the cream. Add the vanilla and scotch and stir until cool over an ice bath. Cover the mixture loosely and let it chill thoroughly in the refrigerator.
Meanwhile, make the buttered pecans. Preheat the oven to 350ºF. Toss the pecans with the melted butter until well coated, then sprinkle with salt. Spread evenly on a baking sheet and toast in the oven until fragrant and lightly crisp, about 10 minutes. Stir the nuts once halfway through cooking. Let the pecans cool and chop coarsely.
Freeze the chilled cream mixture in your ice cream maker according to the manufacturer's instructions. Add the pecans in the last few minutes of churning. Place in an airtight container and store in the freezer for several days.