Step 1

Place the pecans in a food processor and pulse 6 to 8 times, just until they are coarsely chopped.

Step 2

Line a baking sheet with parchment paper. In a fry pan over medium heat, melt the butter. Add half of the pecans and toast them, stirring constantly, until fragrant, 2 to 3 minutes. Sprinkle the 2 Tbs. brown sugar over the pecans and cook, stirring constantly, until the sugar melts and forms a glaze. Scrape the pecans and all of the glaze onto the parchment-lined baking sheet and spread them out in a single layer. Let cool to room temperature.

Step 3

Place the remaining pecans in a dry saucepan over medium-low heat and toast them, stirring constantly, until golden and fragrant, 3 to 4 minutes. Add the cream, milk and the 2/3 cup brown sugar. Warm the mixture, stirring occasionally, until the sugar is dissolved and steam begins to rise from the surface, 3 to 4 minutes. Remove from the heat and let the mixture steep for 10 to 15 minutes.

Step 4

In a bowl, whisk together the egg yolks and salt until blended. Form a kitchen towel into a ring and place the bowl on top to prevent it from moving. Whisk in 1/2 cup of the pecan cream until smooth and blended, then pour the egg mixture back into the pan. Cook over medium-low heat, stirring slowly and continuously with a wooden spoon or spatula, until the custard thickens and a finger drawn across the back of the spoon leaves a path, 8 to 10 minutes; do not allow the custard to boil.

Step 5

Pour the custard through a fine-mesh sieve set over a clean bowl; discard the pecans. Nestle the bowl in a larger one filled halfway with ice and water and cool the custard to room temperature, stirring occasionally. Refrigerate until chilled, at least 1 hour.

Step 6

Stir the vanilla into the custard. Transfer the custard to an ice cream maker and freeze according to the manufacturer's instructions. At the end of the freezing stage, add the buttered pecans and continue processing just until they are blended into the ice cream. Transfer the ice cream to a chilled container, cover and freeze until firm, at least 3 hours or up to 3 days, before serving.