Make the Cupcakes
Preheat oven to 350°F (175°C). Line a muffin tin with cupcake liners.
In a bowl, whisk flour, ground pistachios, baking powder, and salt.
In another bowl, cream butter and sugar until light and fluffy.
Beat in eggs one at a time, then add vanilla and almond extract.
Add dry ingredients alternately with milk, mixing just until combined.
Divide batter evenly among liners, filling about ⅔ full.
Bake for 18–22 minutes, until a toothpick inserted comes out clean.
Cool 5 minutes in the pan, then transfer to a wire rack to cool completely.
Make the Strawberry Buttercream
Blend strawberries into a smooth puree.
Simmer puree in a small saucepan for 10–15 minutes, until reduced and thick. Cool completely.
Beat butter until creamy.
Gradually add powdered sugar, then beat in cooled strawberry reduction, vanilla, and salt.
Beat until light, fluffy, and pipeable.
Assemble
Frost cooled cupcakes using a piping bag or spatula.
Garnish with chopped pistachios or sliced strawberries if desired.