In KitchenAid cream together butter, sugars and vanilla.
Stir in eggs, one at a time.
In separate bowl whisk together flour, salt, cornstarch and baking soda.
With mixer on low-medium speed, gradually add flour mixture to butter/sugar mixture, pausing periodically to scrape down sides of bowl with spatula.
Drop cookie dough by 1 ½" balls into cups of two mini-muffin tins and bake on 350F for 10-12 minutes (until slightly golden-brown around edges).
Remove cookies from oven and allow to cool for 1 minute before creating a crater in the center of each cup by pressing hole halfway into cup using rounded teaspoon (or similar utensil).
Allow cookies to cool completely in muffin tins before filling.
In KitchenAid (or with hand mixer) cream together cream cheese, sugar and vanilla, pausing to scrape down sides of bowl.
Increase mixer speed to medium and gradually add in heavy cream, increasing speed to high and beating for one minute. Pause to scrape down sides of bowl and then beat again on medium-high for another 30 seconds.
Reduce speed to low and stir in sour cream.
Gradually stir in powdered sugar.
Scoop or pipe cheesecake filling into cookie cups. Keep uneaten cookie cups refrigerated in airtight container.