Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a mixing bowl, combine flour, baking powder, and salt. In another bowl, cream together the butter and sugar until light and fluffy. Beat in the egg, vanilla extract, lemon zest, and lemon juice. Gradually mix in the dry ingredients and fold in the chopped rhubarb.
Drop tablespoons of dough onto the prepared baking sheet. Bake for 12-15 minutes or until the edges are golden. Let cool before dusting with powdered sugar if desired.
Notes
Store cookies in an airtight container for up to a week.
Keyword lemon cookies, Rhubarb Cookies, soft cookies