Cooking these Peach Pie Crumble Bars is simple if you carefully follow the steps outlined below:

1. Preheat the Oven: Set your oven to 350°F (175°C) and grease a 9×9-inch baking pan.
2. Prepare the Crust: In a mixing bowl, combine flour, granulated sugar, melted butter, vanilla extract, baking powder, and salt. Mix thoroughly until crumbly.
3. Press Into Pan: Reserve 1 cup of the mixture for the topping. Press the remaining mixture evenly into the bottom of the prepared baking pan.
4. Prepare the Filling: In another bowl, mix sliced peaches with lemon juice, cinnamon, and a tablespoon of sugar. Toss until coated.
5. Spread Filling: Distribute the peach filling evenly over the crust in the baking pan.
6. Add Topping: For the topping, combine the reserved crumb mixture with oats and brown sugar. Sprinkle evenly over the peach layer.
7. Bake: Bake in the preheated oven for 30-35 minutes or until the top is golden brown and the peaches are bubbly.
8. Cool: Allow the bars to cool in the pan for about 15-20 minutes before transferring to a wire rack to cool completely.
9. Cut and Serve: Once cooled, cut the bars into squares for easy serving.

These simple steps will guide you in creating delicious Peach Pie Crumble Bars that everyone will adore.