0 Place 1 cup of pistachios in a food processor and process for about 5 minutes, scraping down the sides every minute, until it forms a sand-like consistency. Add the 3 teaspoons olive oil and then process again for 3 more minutes, or until it achieves a nut-butter consistency.
1 In a large bowl, add the softened butter, sugar, and 3 tablespoons of the pistachio butter. Beat with an electric mixer until fluffy. Then mix in the eggs, vanilla, and milk
2 In a large bowl, whisk together the flour, baking powder, baking soda, and 1/4 teaspoon salt. Add half of the flour mixture to the wet, beat until incorporated, then add in the rest of the flour mixture and mix until evenly combined.
3 Grease a 9x13" pan with 1 teaspoon of spray oil and pour the batter in. Spread out as best you can (some gluten-free flours can be gummy at this stage and hard to spread - just keep working with it, the results will be great). Bake at 350F for 15-20 minutes, or until a toothpick comes out clean the top is lightly golden.
4 Let the cake cool completely before making the frosting.
5 For the frosting, add the cottage cheese to the food processor with the remaining pistachio butter and blend until smooth, about 3 minutes. Pour into a bowl and add the powdered sugar and 1/4 teaspoon salt. Beat with a mixer until smooth.
6 Once the cake is cooled, pour the frosting over the cake and spread out into an even layer. Roughly chop the remaining 1/4 cup of shelled pistachios and sprinkle over the top. Cut into pieces and enjoy!
