Preheat oven to 250F. Rub 2 tablespoons butter over bottom and up sides of 10 inch diameter springform pan with 3 inch high sides. Add pecans, shaking and turning pan to coat bottom and sides. Mix cracker crumbs with remaining 1/2 cup butter in small bowl. Press into bottom of pan.
Using electric mixer, beat cream cheese in large bowl until softened. Add sugar, eggs, yolks and vanilla and beat until smooth. Fold in sour cream. Pour batter into prepared pan. Bake until knife inserted 2 inches from center comes out clean, about 1 1/2 hours. Turn off oven. Leave cheesecake in oven 20 minutes. Transfer to rack and cool completely. Refrigerate overnight.
