Creating these delicious Peaches and Cream Crumble Bars can be accomplished by following these clear steps:

1. Preheat the Oven: Begin by preheating your oven to 350°F (175°C). Grease a 9×13 inch baking dish.

2. Prepare the Peach Filling: In a mixing bowl, combine the diced peaches, lemon juice, granulated sugar, vanilla extract, and cornstarch. Toss gently until the peaches are well coated, then set aside.

3. Make the Crumble Base: In another bowl, mix together the flour, rolled oats, brown sugar, baking powder, and salt. Add the cold, cubed butter to the mixture. Using a fork or your fingers, work the butter into the mixture until it resembles coarse crumbs.

4. Assemble the Base: Press half of the crumble mixture evenly into the bottom of the prepared baking dish. Spread the peach filling over the crumble base, ensuring even coverage.

5. Prepare the Cream Cheese Layer: In a separate bowl, beat together the softened cream cheese, powdered sugar, and vanilla extract until smooth and creamy.

6. Layer the Cream Cheese: Spoon the cream cheese mixture over the peaches, spreading it gently to avoid disturbing the peaches too much.

7. Top with Remaining Crumble: Crumble the remaining mixture over the cream cheese layer, covering it completely.

8. Bake: Place the dish in the preheated oven and bake for 30-35 minutes, or until the top is golden brown and crisp.

9. Cool Down: Once baked, remove from the oven and allow to cool at room temperature for 1-2 hours. This will help the layers set.

10. Slice and Serve: Cut into squares and serve as desired. Enjoy the blend of flavors in each bite!

By following these steps, you will create decadent Peaches and Cream Crumble Bars that will leave everyone craving more.