• Place the pistachios in a food processor and pulse until they become fine crumbs. Set aside.
• Preheat the oven to 350°F (177°C). Line a 12-cup muffin pan with cupcake liners and prepare 3 additional liners in a second pan.
• In a medium bowl, whisk together the cake flour, baking powder, baking soda, salt, and ¾ cup of the pistachio crumbs. Reserve the remaining crumbs for garnish.
• In a large mixing bowl, beat the butter and sugar on high speed until light and creamy, about 3 minutes.
• Add the egg whites, vanilla extract, and almond extract. Mix until combined.
• Beat in the sour cream until smooth.
• Add the dry ingredients. With the mixer on low speed, slowly pour in the milk and optional food coloring.
• Mix only until combined. Avoid overmixing to keep the Pistachio Cupcakes with Strawberry Buttercream light and fluffy.
• Fill cupcake liners about two-thirds full.
• Bake for 19–22 minutes or until a toothpick inserted in the center comes out clean.
• Remove from the oven and allow the cupcakes to cool completely.

Make the Strawberry Buttercream

• Process the freeze-dried strawberries into a fine powder using a food processor or blender.
• In a large bowl, beat the butter until creamy, about 2 minutes.
• Add the confectioners' sugar, strawberry powder, cream, and vanilla extract.
• Beat on low speed for 30 seconds, then increase to high speed and beat for 2 minutes until fluffy.
• Taste and add a pinch of salt if desired.
• Pipe or spread the frosting onto the cooled cupcakes.
• Garnish with reserved pistachio crumbs and fresh strawberry slices if desired.