From the blog For Love of the Table
55 g. pistachios, lightly toasted (see notes) and very finely ground (a scant 1/2 c.—measured before grinding)
170 g. sifted cake flour (1 3/4 c.—sifted into the cup ans leveled off)
225 g. sugar (1 c. plus 2 T.)
2 1/2 t. baking powder
1/2 t. Salt
70 g. unsalted butter, at a cool room temperature (5 T.)
4 oz. finely chopped semi-sweet chocolate
2 eggs, room temperature
1 t. vanilla
72 g. vegetable oil (1/3 c.)
160 g. whole milk (2/3 c.)
Place the first five ingredients in a large bowl and whisk to combine. Slice the butter in 1/4-inch thick slices and add to the bowl. Rub the butter into the dry ingredients until the mixture looks like stone ground cornmeal (you may do this by hand or in a stand mixer fitted with the paddle attachment). Add the chocolate and toss to combine. Set aside.
Place the eggs and vanilla in a small bowl and whisk until smooth. Whisk in the oil in a steady stream. Whisk in the milk. Add the wet to the dry and mix until well blended. The batter will be quite thin.
Scoop the batter (I use a scant 2 oz. ice cream scoop...or a mounded 1 1/2 oz.) into muffin tins lined with paper liners—the cups should be 2/3 to 3/4 full. Bake in a preheated 375° oven until light golden, springy to the touch and a toothpick comes out clean—about 18 to 22 minutes. Cool in the tins for 5 to 10 minutes. Transfer to a wire rack and cool completely. Frost with cream cheese frosting and garnish with minced toasted pistachios, green sanding sugar or finely grated chocolate. Makes 16 to 18 cupcakes.
Notes:
To toast the pistachios, spread on a baking sheet and place in a 350° oven. Bake, stirring once or twice, until fragrant—about 5 minutes.
To make pistachio nut flour, grind the cooled nuts with a rotary nut grinder.
If you don't have nut grinder, place the cooled nuts in the food processor with the sugar and process until fine. I have not tested the recipe this way, but I suspect that one could finish mixing the dry ingredients in the food processor: After grinding the pistachios with the sugar, add the flour, baking powder and salt and process to combine. Add the butter and process until the mixture looks like coarse meal. Transfer the contents of the processor to a large bowl, add the chocolate and proceed with the recipe.
(Recipe adapted from Better Homes & Gardens and Cupcake Project)
http://www.forloveofthetable.com/2014/03/pistachio-cupcakesfor-st-patricks.html