Preheat oven to 350 degrees F. Line a baking sheet with silicone baking mat or parchment paper. Set aside.
In a large mixing bowl, beat butter, vegetable oil, 1 1/4 cup granulated sugar, powdered sugar, water, and eggs until combined. Slowly add in flour, baking soda, cream of tartar, and salt. Mix until blended.
Dough may be slightly crumbly, but should not be sticky. Using a spoon, spoon out a dough ball and roll it in your hands. (I like to make bigger cookies but its up to you on the size, but at least a spoonful) Place on cookie sheet.
In a small bowl, combine 1/4 cup granulated sugar and a pinch of sea salt.
Using a glass cup with a flat bottom, dip glass in sugar bowl, then press on top of cookie. Flatten cookie so that the dough spills out over the sides of the glass to create a lip (for the icing). Repeat for all dough balls.
Bake cookies for 7-9 minutes. Remove and cool completely on wire rack.
For the icing, beat together the butter and sour cream until well blended. Add in powdered sugar and food coloring, beating until well blended.
With the back of a metal spoon, spread the frosting onto the cookies
Now try not to eat them all!