Combine cornstarch, lemon juice, and warm water in a bowl. In a saucepan, cook raspberries and sugar over medium heat for about 3 minutes, stirring constantly. Add the cornstarch mixture and cook for another 3 minutes, mashing the raspberries. Blend and strain to remove seeds. Set aside to cool.

Preheat oven to 325°F (163°C). Combine graham cracker crumbs, melted butter, and sugar. Press into the bottom and sides of a springform pan. Bake for 10 minutes, then let cool.

Lower oven temperature to 300°F (148°C). Beat cream cheese, sugar, and flour until smooth. Add sour cream, lemon juice, and zest. Mix in eggs and yolks one at a time.

Pour three-quarters of the cheesecake filling into the crust. Drop spoonfuls of raspberry filling and swirl gently. Add remaining filling and raspberry, then swirl again.

Wrap the springform pan in aluminum foil. Place in a larger pan with warm water. Bake for 1 hour 25 minutes. Turn off oven, leave cheesecake for 30 minutes, then open door for another 30 minutes. Refrigerate for several hours or overnight.