Grind one cup pistachios and 1/4 cup sugar in food processor to a fine powdery consistency.

Combine ground pistachio mixture and milk in a large saucepan and bring to a boil.

Remove mixture from heat and stir in almond extract.

In a medium bowl, whisk remaining sugar and egg yolks together. Slowly whisk in pistachio mixture, and then return the entire mixture to the saucepan.

Cook on low for about 10 minutes without boiling, stirring constantly, or until custard mixture thickens.

Strain into a large bowl (this step may be challenging, depending on how finely you were able to grind the pistachios - if you have trouble, try using a bowl or a spoon to press the liquid down through the strainer).

Chill for about 2 hours.

Stir whipping cream into custard, and start ice cream maker. Pour custard mixture into ice cream maker bowl, and prepare according to manufacture's directions (usually about 25-35 minutes, or until desired consistency is reached).

Scoop into bowls and freeze any remaining ice cream in a covered container.

Chop remaining pistachios and sprinkle over scooped ice cream in bowls, if desired.