In a small skillet, melt the butter over medium heat. Add the chopped pecans and a pinch of salt. Toast them in the butter, stirring often, for about 4 to 5 minutes until fragrant and golden.
Spread the pecans on a plate and let them cool completely. These buttery toasted pecans will add incredible flavor and crunch. In a medium saucepan, heat the heavy cream, almond milk, and erythritol over medium heat, stirring until the sweetener dissolves. Bring it just to a simmer, then remove from heat.
In a bowl, whisk the egg yolks. Slowly drizzle about 1/2 cup of the hot cream mixture into the yolks while whisking constantly to temper them. Then pour the egg mixture back into the saucepan.
Cook the custard over medium-low heat, stirring constantly with a spatula, until it thickens enough to coat the back of a spoon, about 5 to 7 minutes. Do not let it boil.
Strain the custard through a fine mesh strainer into a clean bowl. Stir in the vanilla extract and remaining salt. Press plastic wrap directly onto the surface of the custard and refrigerate until completely cold, at least 4 hours or overnight.
Churn the chilled custard in an ice cream maker according to the manufacturer's instructions. Fold in the buttered pecans during the last 2 minutes of churning.
Transfer the ice cream to a freezer-safe container and freeze for at least 2 hours for a firmer scoop. Let it sit at room temperature for 5 minutes before serving.
