Spray a 24-well mini muffin pan with nonstick cooking spray. Set aside.
In a medium bowl, combine butter and sugar. Beat at medium speed with an electric mixer until creamy. Add egg and vanilla extract, beating to combine. Set aside.
In a small bowl, combine flour, baking powder, and salt, whisking until combined. Gradually add flour mixture to butter mixture, beating until combined.
Divide dough evenly into 24 balls. Press a dough ball into bottoms and up sides of each well of prepared pan to form a cup.
Bake until edges are light golden brown, approximately 10 minutes. Remove from oven, and immediately press the back of a rounded measuring spoon down into the warm cookies to form cups. Let cool in pan for 5 minutes, and then carefully remove cookie cups to a wire rack to cool completely.
Store in an airtight container for up to 2 days.
Recipe by TeaTime Magazine at https://teatimemagazine.com/sugar-cookie-cups-strawberry-cream/