Adapted from a recipe by Smitten Kitchen
You are going to need a food processor for this. Make sure - when roasting the pistachios - you watch them like a hawk or set a timer - at their price you won't want to waste one because of burning. The original recipe calls for 1/2 tsp of almond extract - to be added at the same time as the vanilla. I'm not a fan, so I omitted it but if you like it, by all means throw it in.
140g roasted, shelled, and unsalted pistachios
1/2 tsp sea salt
145g unsalted butter, cold is fine
3 large eggs
1/4 cup milk
1/2 tsp vanilla extract
Slightly heaped 1/2 tsp baking powder
40g roasted, shelled, and unsalted pistachios
Finely grated zest and juice of 1 lemon
Heat oven to 325 degrees F.
Line the bottom and long sides of a loaf pan with a sling of parchment paper. Grease paper and exposed short sides of loaf pan with nonstick spray or butter.
In a food processor, grind pistachios, sugar and salt together until as powdery as you can get them without it turning to paste. Cut butter into small chunks and blend with pistachio mixture. It will be lumpy at first, and then balled for a minute, but keep running the machine until the mixture loosens up into a frosting-like consistency, i.e. smooth and shiny. Add eggs, one at time, blending briefly between each, scraping down sides as needed. Add milk, blend to combine. Add vanilla and baking powder and blend to fully combine, scraping down bowl. Add flour and pulse just until it disappears.
Scrape batter into prepared pan and spread top smooth. Bake for 60 to 70 minutes. Look for a toothpick inserted into the centre of the cake to come out clean. If you're on the fence, put the cake back in for 5 minutes on a lower rack.
Let cake cool in pan for 10 to 15 minutes, then run a knife around cake and transfer to cooling rack to let cool completely.
Bring pistachios, sugar, zest, and juice to a simmer in a small saucepan; simmer for 2 to 3 minutes then pour over cooled cake.