Preheat your oven to 350°F (175°C). Grease a 9x13 inch baking dish.

In a large bowl, combine the flour, granulated sugar, softened butter, egg, vanilla extract, and salt. Mix until crumbly and well combined.

Press two-thirds of the mixture into the bottom of the prepared baking dish to form the base.

In a medium bowl, combine the sliced peaches, brown sugar, cornstarch, and lemon juice. Toss gently to coat the peaches evenly.

Spread the peach mixture evenly over the base in the baking dish.

In another bowl, mix the rolled oats, brown sugar, melted butter, and cinnamon until crumbly.

Sprinkle the oat mixture over the peach filling evenly.

Bake in the preheated oven for 30-35 minutes, or until the topping is golden brown and the peach filling is bubbling.

Remove from the oven and let cool in the pan for at least 15 minutes before slicing into bars.

Cut into squares and serve warm or at room temperature. Enjoy!