01 - 
                Preheat the oven to 350°F and prepare a 9×13-inch baking dish. Mix the flour, oats, brown sugar, and melted butter in a bowl. Press the mixture into the prepared dish and bake for 15 minutes.
              
              
              
                02 - 
                In a saucepan, cook the rhubarb, granulated sugar, and cornstarch over medium heat until the mixture thickens. Stir in the vanilla extract.
              
              
              
                03 - 
                Spread the rhubarb mixture evenly over the baked crust. Return to the oven and bake for an additional 10–15 minutes.
              
              
              
                04 - 
                In a mixing bowl, beat the cream cheese, powdered sugar, and vanilla until smooth and creamy.
              
              
              
                05 - 
                Spread the cream cheese mixture over the cooled rhubarb layer. Chill the bars in the refrigerator for at least 2 hours.
              
              
              
                06 - 
                Cut the chilled bars into 16 squares using a clean knife and serve.