Preheat the oven to 350° and lightly grease a baking sheet or use parchment paper.

In a medium bowl, whisk together flour, baking powder, and salt. Set this mixture aside.

In a large bowl, add the softened butter, vegetable oil, and sour cream. Beat on medium speed for one minute until mixed well.

Next, add the sugar and vanilla extract, and continue to beat until the mixture is smooth.

Gradually mix the dry ingredients into the wet mixture on low speed just until the dough forms a ball.

Use a two-inch cookie scoop to scoop out the cookie dough and place it on the prepared baking sheet, leaving the edges rough for a rustic look.

With the bottom of a glass, gently flatten each cookie to enhance the jagged edges.

Bake in the oven for 10-12 minutes or until the edges start to turn slightly brown.

Remove the cookies from the oven and let them cool for 5 minutes before transferring them to a wire rack to cool completely.

In a medium mixing bowl, cream together butter, milk, and vanilla.

Gradually add the powdered sugar and beat until smooth and creamy.

If you want colored frosting, add gel coloring and mix until you get your desired color.

Once the cookies are completely cool, frost them generously with the buttercream, sprinkle with coarse sugar, and add festive Easter sprinkles.

Allow the frosting to set, and then store the cookies with parchment paper between layers.