Preheat oven to 450 ℉
Place the chopped peaches in a fine-mesh sieve or colander set over a bowl and allow the excess juice to drain for 10–15 minutes.
In a large bowl, whisk together the flour, baking powder, baking soda, sugar, and salt until well combined.
Add the cold butter and cut it into the flour mixture with a pastry blender or your fingertips until evenly distributed and the mixture resembles coarse crumbs.
Pat the peaches dry with a paper towel to remove any excess moisture.
Add the peaches and milk and mix just until the dry ingredients are moistened—do not overmix.
Turn the dough onto a floured surface and knead gently just until it holds together—avoid overworking.
Cut the dough in half and gently pat each piece into a disk. Lightly roll each disk into a 6-inch circle, then place on an ungreased baking sheet. Brush the tops with beaten egg and score each circle into 6 wedges.it
Bake for 20 minutes, or until the tops are golden brown. Remove from the oven and allow to cool on a wire rack before serving.