Bring all ingredients to room temperature and Preheat your oven to 375°.
Prepare crust by combining Crushed Graham Crackers, 1/4 Sugar and 1/2 cup Melted Butter and pressing into your greased 9" Spring Form Pan. Bake in preheated oven for 10 minutes or until golden brown. Allow Crust to cool while making your filling.
Cream together Butter and Cream Cheese until combined and no lumps remain. Add Sugar and Cornstarch and mix until combined. Add Sour Cream and Whipping Cream and mix again until combined. Add Lemon Juice and Vanilla. Mix until combined. Add Eggs and Egg Yolks to mixture one at a time, mixing slowly until fully combined. But DO NOT over mix! Pour filling into cooled crust.
Wrap your pan in a layer of Plastic Wrap sandwiched in between 2 layers of Heavy Duty Aluminum Foil. Make a water bath by placing a pan (big enough for your Spring Form Pan to fit easily within it) into your preheated oven and fill with about an inch of water. Place your wrapped Cheesecake into the water bath and bake for 50 minutes. After 50 minutes, decrease your temperature to 350° and bake for 45-55 minutes more or until the edges are set but center is still wobbly.
When Cheesecake is baked, turn off your oven and prop the door open just slightly with a folded kitchen towel or oven mitt and allow your Cheesecake to cool in the oven for at least 2 hours. When it is cool, cover the pan in plastic wrap and place it into the freezer overnight. If you don't want to have to thaw your cheesecake you can place it directly into the fridge and chill at least 8 hours. Freezing it helps the texture develop, but it IS optional.
When properly cooled or frozen, slide a knife around the edge of your Cheesecake and remove it from the pan. If your cheesecake was frozen, give it an hour or two outside of the fridge to soften. Serve cold with your favorite toppings.
Cheesecake can be covered and stored in the refrigerator for up to a week. Or wrapped and frozen for up to 3 months.