Preheat the oven to 350 F and line an 8x8 inch or 9x9 inch baking pan with parchment paper. 

To make the crust and the topping:  in a medium sized bowl, combine old fashioned rolled oats, flour, cinnamon, salt, brown sugar and melted butter and mix until well combined. The mixture should be crumbly. Press half of the mixture on the bottom of the baking pan, to make an even, solid layer. Save the rest for the topping. 

To make the cheesecake layer: In a larger bowl, beat softened cream cheese, at medium speed until smooth. Add flour, sugar, vanilla and beat some more until smooth and creamy. Scrape down the sides of the bowl when you finish. Add an egg and beat until combined, then spread evenly over the crust.

To make the blueberry filling: in a medium sized dish toss blueberries with lemon juice. Add flour, corn starch and sugar, then stir. Sprinkle blueberries gently over the cheesecake layer. Finally, sprinkle the remaining crunchy dressing on top of blueberries. Bake for  55-60 min or until the topping is golden brown and the middle is only slightly jiggly. Take out of the oven when it’s done and leave in the pan to cool completely at room temperature, for about 2 hours. Transfer to the fridge for at least 4 hours. Cut into cubes before serving.