Preheat your oven to 350°F (175°C). Lightly grease a 9x9-inch baking dish or a similar-sized dish.

In a large mixing bowl, combine the sliced peaches, granulated sugar, lemon juice, and vanilla extract. Toss until the peaches are evenly coated and transfer them to the prepared baking dish.

In another bowl, mix together the flour, rolled oats, brown sugar, cinnamon, and salt. Pour the melted butter into the dry ingredients and stir until it forms a crumbly mixture.

Sprinkle the crumble mixture evenly over the peaches in the baking dish.

Bake in the preheated oven for 40-45 minutes, or until the topping is golden brown and the peach filling is bubbling.

Allow the peach crisp to cool for about 10 minutes before serving. Serve warm on its own or with a scoop of vanilla ice cream.