Preheat the oven to 350 degrees F (175 degrees C).

Combine 2 cups flour and 1/4 cup sugar in a bowl. Cut butter into flour mixture until it resembles coarse crumbs; press into a 9x13-inch baking dish.

Bake in the preheated oven until crust is lightly browned, about 10 minutes.

Mix 2 cups sugar and 7 tablespoons flour together in a bowl; whisk in heavy whipping cream and eggs until smooth.

Spread rhubarb evenly over crust. Pour egg mixture over rhubarb.

Bake in the preheated oven until bars are set, about 45 minutes. Cool to room temperature, about 30 minutes.

Beat cream cheese, remaining 1/2 cup sugar, and vanilla extract together in a bowl until smooth and creamy; fold in whipped topping. Spread cream cheese mixture over rhubarb layer; chill in refrigerator.