- Preheat an oven to 350°F.
- Arrange the pistachios in a single layer on a baking sheet and bake, shaking the pan occasionally, until the nuts are lightly golden and toasted, 5 to 7 minutes. Let cool to room temperature.
- In a mini-food processor or standard-size food processor, combine 1/2 cup of the pistachios with the sugar and process until finely chopped and well blended. Reserve the remaining 1/2 cup pistachios.
- In a saucepan, combine the milk, cream and the pistachio-sugar mixture and stir to blend. Set the pan over medium-low heat and 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.
- 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 pistachio-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.
- Pour the custard through a fine-mesh sieve set over a clean bowl; discard the pistachios. 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.
- Stir the almond extract into the custard, transfer to an ice cream maker and freeze according to the manufacturer's instructions. At the end of the freezing stage, add the remaining 1/2 cup pistachios 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. Makes about 1 quart.