Combine all crust ingredients. Mix until crumbly. Press into a greased 9 x 13 baking pan. Bake for 12-15 minutes or until light brown.
For the blueberry ribbon:
In a small sauce pan over medium heat combine 3 cups of blueberries, sugar and lemon. Cook over medium heat stirring often for about 15 minutes or until mixture begins to thicken. Remove from heat.
Cool slightly. Spread evenly over oat crust. Arrange 1 cup of blueberries over top of blueberry syrup.
For the cheesecake:
Beat cream cheese until smooth in a large mixing bowl on medium speed for 2-3 minutes. Gradually add sugar. Beat in eggs, one at a time. Mix in vanilla.
Pour the filing over the blueberries. Bake the bars until the edges are set but the center still jiggles slightly, about 35-40 minutes.