Preheat your oven to 400°F (204°C). Grease a 9x9-inch baking pan with a bit of butter or nonstick spray to prevent sticking, then set it aside for later use.

In a large bowl, combine the peeled and thinly sliced peaches, granulated sugar, 2 tablespoons of all-purpose flour, cornstarch, 1 teaspoon ground cinnamon, and salt. Mix everything together until the peaches are well coated with the sugar and dry ingredients. Pour this peach mixture evenly into the prepared baking pan.

In the same large bowl (no need to wash it), cream together the packed light brown sugar, the remaining 1/2 cup all-purpose flour, room temperature salted butter, and the remaining 1 teaspoon ground cinnamon. Mix until the ingredients form a wet, clumpy mixture. Add the old-fashioned oats and stir until the topping is well combined and coarse. I find it easiest to use my hands for this step, as it helps the mixture come together more quickly.

Crumble the oat topping (from Step 3) evenly over the peach filling (from Step 2) in the baking pan. Place the pan on the center rack of the oven and bake for 20 to 25 minutes, or until the oats turn a light golden color around the edges. Remove the crisp from the oven and allow it to rest on a wire rack for about 10 minutes. This cooling time helps the filling set up before serving.

Serve the peach crisp warm, optionally topping it with a scoop of vanilla ice cream for extra indulgence. I always add ice cream on top – it’s the perfect match for the warm, bubbly peaches and crisp oat topping.