Preheat oven to 350°F (175°C) and line a baking sheet with parchment.
Beat ricotta, butter, and sugar until light and fluffy.
Mix in egg and vanilla.
Whisk flour, baking powder, and salt in a separate bowl.
Combine wet and dry mixtures, then fold in pistachios.
Roll tablespoon-sized balls in sugar and arrange on sheet.
Bake 12–14 minutes until edges are golden.
Cool on rack before serving.
