Instructions

Make the whoopie pies:

1. Position a rack in the middle of the oven.  Preheat the oven to 350 degrees F.  Line two baking sheets with parchment paper and butter the paper.
2. Sift together the flour, baking powder, baking soda, and salt into a medium bowl and set aside.  In a large bowl, using an electric mixer on medium speed, beat the butter, sugar and lemon zest until smooth, about 3 minutes. Stop the mixer to scrape the sides of the bowl as needed during the mixing.  Add the egg, lemon juice and vanilla, mixing until blended, about 1 minute. The batter may look curdled. On low speed, add half of the flour mixture, mixing just to incorporate it. Mix in the buttermilk.  Mix in the remaining flour mixture just until it is incorporated and the batter looks smooth again.
3. Drop heaping tablespoons (about 3 level tablespoons each for a giant cookie) of dough onto the prepared baking sheets, spacing them about 3 inches apart. Bake the cookies one sheet at a time until toothpick inserted in the center comes out clean and the tops feel firm, about 12 minutes. With the exception of a time line at the edges, the tops of the cookies should not brown. Cool the cookies on the baking sheets for 10 minutes, then use a wide metal spatula to transfer them to a wire rack to cool completely.

Make the pistachio ice cream:

1. Preheat oven to 350F.
2. Spread pistachios onto a small baking sheet and toast in oven for 10-12 minutes, until fragrant and starting to turn brown. Remove from oven.
3. Roughly chop 1/2 cup roasted pistachios and reserve for mixing in later. Place the other 1/2 cup in a food processor and process until you get a smooth paste.
4. In a small bowl, make a slurry with 2 Tbsp of milk and the cornstarch. Set aside.
5. In a medium bowl, whisk the cream cheese, pistachio paste, and salt.
6. Combine the remaining milk, cream, sugar, and corn syrup in a 4-qt saucepan. Bring to boil over med-high heat and boil for 4 minutes. Remove from heat and whisk in slurry.
7. Bring mixture back to a boil over med-high heat and cook until slightly thickened (~1 minute). Remove from heat.
8. Whisk the hot milk mixture in to the cream cheese mixture until smooth. Refrigerate at least 4 hours, or overnight, until completely cool.
9. Process in ice cream maker according to manufacturer’s instructions. Add the almond extract after adding the ice cream to the ice cream maker.
10. Layer the ice cream with chopped pistachios in a storage container and freeze until firm, at least 4 hours.