Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large bowl, cream together the butter and powdered sugar until light and fluffy. Stir in vanilla extract.
Gradually add the flour to the butter mixture, mixing until just combined. Fold in the sprinkles.
Roll the dough into small balls and place them on the prepared baking sheet. Flatten them slightly with a fork.
Bake for 12-15 minutes, or until the edges are lightly golden. Allow to cool completely before assembling cookie sandwiches with your favorite filling.
Notes
You can fill these cookie sandwiches with buttercream, chocolate ganache, or your favorite sweet filling.