Preheat the oven to 350 degrees Fahrenheit. Line baking sheets with parchment paper or silicone mat and set aside.

In a large bowl, whisk together flour, baking powder, baking soda and salt.

In a different large bowl, cream together butter, sour cream and sugar until light and fluffy. Mix in egg and vanilla extract until combined.

Gradually add dry ingredients to the wet ingredients, scraping down the bowl after each addition, mix until well combined.

Roll cookies into 2 inch balls and place on lined baking sheets.

Dip the bottom of a glass into water and slightly flatten cookie dough balls.

Bake for 8-10 minutes in a preheated oven at 350 degrees F or until cookies are puffed slightly, set and bottoms are lightly browned.

Remove from the oven and let cool for 2 minutes before transferring to the wire rack. Allow to cool completely.

While the cookies are cooling, mix together the frosting. Add all the frosting ingredients to a small mixing bowl and mix with a hand mixer until smooth.

Once cookies are cooled all the way, frost them and enjoy.