Directions

1. Heat 2 1/2 cups of the half-and-half in a large saucepan over medium heat until small bubbles begin to form around the edges. Remove from heat and set aside.
2. Mix the egg yolks and sugar in a large bowl until smooth. While stirring, slowly pour the half-and-half into the egg mixture. Transfer the mixture to the saucepan and heat again over medium heat until bubbles begin to form around the edges. Remove from heat and return to the bowl. Stir in the heavy whipping cream.
3. Puree the bananas and 3/4 cup half-and-half in a blender until smooth. Add puree to bowl and mix well. Cover and refrigerate until cold, 3 to 4 hours.
4. Pour mixture into cylinder of ice cream freezer. (Refrigerate any remaining mixture until ready to freeze.) Freeze according to the manufacturer's directions. Stir in the walnuts. Transfer to 1 quart containers and freeze overnight before serving.