Preheat oven to 350°F.

In the bowl of a food processor, grind biscuits into a fine powder.

Add in melted butter and pulse until the mix is uniformly coated with butter.

Transfer the mix into a 12-inch springform cheesecake pan and evenly pat on the bottom.

In the bowl of an electric mixer fitted with the whisk attachment, start creaming cream cheese, sour cream, and powdered sugar on low speed.

Add in eggs, zests, and vanilla and continue mixing. Sift in flour and potato starch and beat slowly until the mix is smooth and creamy, about 8 minutes.

Pour cheesecake mix into the pan and bake in a 350°F oven for 15 minutes, and then lower the heat to 285°F and continue baking for 30 minutes.

Mix sour cream and powdered sugar and pour over slightly cooled cheesecake. It has to still be warm in order to smooth out sour cream.

Chill cake for a minimum of 8 hours.