Prepare cookie crust: Place butter and sugar in mixer bowl and mix till fluffy, about 3 minutes, scraping often. Add yolks and mix thoroughly. Add vanilla and salt, and then flour. Allow to mix till it forms a ball and then remove from bowl and place on floured surface. Roll into a circle and place bottom of 10" springform pan over dough and cut around it with a knife a little smaller (about 1/4") than the pan bottom. Transfer to cookie sheet covered with parchment and bake at 350° for 15-18 minutes or till JUST browned on edges. Cool completely.
Place softened cream cheese in mixer bowl and mix till smooth--this takes patience, because it's a lot of cream cheese and you have to scrape and work with it to get it mushed together --
Add sugar and flour and mix thoroughly. Add eggs one at a time mixing between each one, and then add sour cream and vanilla.
Butter sides of springform pan and place cookie crust in the bottom--trim to fit if needed. Pour filling on top of crust and smooth the top. Bake in a 350° oven for 90 minutes and then reduce heat to 325° for another 15-20 minutes to set center. Turn oven off and leave cake inside -- prop door open and allow cake to cool completely, then remove, cover with plastic wrap and refrigerate till serving time. Top with fresh fruit or canned pie filling, or fresh whipped cream.