Preheat oven to 350 degrees and line two cookie sheets with parchment paper
Using a large bowl, beat together the butter, oil, sugars, water and vanilla until combined and smooth
Beat in the eggs one at a time until combined
Using a large bowl, whisk together the flour, salt, baking soda and cream of tartar
Gradually beat in the dry ingredient into the wet ingredients until a soft dough forms
Using a mini ice cream scooper, scoop out some dough and roll it into a ball and place onto the cookie sheet
Using a flat bottom of a glass, lightly press the dough ball into a thick disk
Using the back of a spoon, make a indent into the cookie
Repeat steps for more cookies
Place into the oven and bake for 8 minutes
Allow to cool