Heat oven to 350°F.
Combine rhubarb, 1/2 cup sugar and flour in a non-stick skillet. Cook over medium heat until sugar melts. Pour into bottom of prepared pie crust.
Meanwhile, beat together cream cheese, 1/2 cup sour cream and 1/2 cup sugar until fluffy. Add eggs, one at a time, and 1 tablespoon vanilla until blended. Pour over rhubarb layer. Bake for 30 minutes or until puffed and golden.
Combine remaining sour cream, sugar and vanilla; spread over hot pie. Set on a wire rack to cool slightly; cover and refrigerate before serving.