For the crust: Preheat oven to 325° F.

Combine flour, sugar, and salt in a medium bowl. With a rigid pastry blender, cut in the butter until crumbly. Press mixture on the bottom and up the sides of a 9" pie pan, aiming for a uniform thickness all over. Do this with a gentle yet firm hand. Set aside.

For the rhubarb filling: In a medium bowl, stir together the rhubarb, sugar, and flour. Spread evenly over the bottom of the pie crust. Bake for 15 minutes, then remove from the oven and set aside.

Increase oven temperature to 350° F.

For the cheesecake layer: In a medium bowl, beat the cream cheese and sugar until creamy, about 1 minute or so. Beat in the eggs, one at a time. Then add the vanilla and beat just to combine. Spread cream cheese mixture evenly over the hot rhubarb in the pie pan (there will be accumulated liquid from the rhubarb). Bake for 25 minutes.

For the sour cream layer: While the cheesecake layer is baking, make the sour cream layer. In a small bowl, stir together the sour cream, sugar, and vanilla. Immediately after the cheesecake layer has baked for 25 minutes, spread the sour cream layer over the center of the pie, leaving about 1/2'' of the cheesecake layer exposed around the edges.

Put the pie back in the oven and bake an additional 15 minutes.

Let cool completely on a wire rack and then chill in the refrigerator for at least 2 hours before serving. Serve with fluffy homemade whipped cream.