Preheat your oven to 375°F (190°C). Grease a 9x13 inch baking dish.

In a large bowl, gently toss the sliced peaches with lemon juice, 1 teaspoon of cinnamon, granulated sugar, and 2 tablespoons of flour until evenly coated.

Spread the peach mixture evenly into the prepared baking dish.

In a separate bowl, combine the rolled oats, 1 cup of flour, brown sugar, 1 teaspoon of cinnamon, and salt. Whisk to combine.

Add the cold, cubed butter to the oat mixture. Using a pastry blender, your fingertips, or a fork, cut the butter into the dry ingredients until the mixture resembles coarse crumbs with some pea-sized pieces.

Sprinkle the oat topping evenly over the peach layer in the baking dish.

Bake for 35-45 minutes, or until the topping is golden brown and the peach filling is bubbly and tender. If the topping starts to brown too quickly, you can loosely tent the dish with foil.

Let the crisp cool for at least 10-15 minutes before serving. Serve warm, perhaps with a scoop of vanilla ice cream or a dollop of whipped cream.