Preheat your oven to 350°F (180°C) and grease an 8-inch cake pan.

Combine sliced peaches with sugar in a medium bowl and let sit for 10 minutes.

Whisk together flour, sugar, baking powder, and salt in a large bowl.

Grate or cut very cold butter into small pieces; mix into dry ingredients until coarse crumbs form.

Add one egg to the mixture and stir until crumbly but clumps when pressed; reserve half for topping.

Press half of the crumb mixture into the bottom of the prepared pan, then top with the peach filling and remaining crumb mixture.

Bake for 30-40 minutes until golden brown and a toothpick comes out clean.

Cool in the pan for 10-15 minutes before transferring to a wire rack to cool completely.