Preheat oven to 180C. Grease friand pan with butter or cooking spray (may use muffin pan if you don't have a friand pan). Process pistachios in a small food processor until ground. Transfer to a bowl. Sift over the icing sugar and flour.
Use a for to whisk egg whites in a large bowl until frothy. Add butter and pistachio mixture. Stir gently until just combined.
Fill prepared pans. Lay mango slices over batter and bake for 25-30 minutes or until firm. Cool in pan for 5 minutes, then transfer to a wire rack to cool completely. Dust with icing sugar or snow powder.recipe adapted from Taste.com
Recipe by Anncoo Journal at https://www.anncoojournal.com/mango-and-pistachio-friands/