Preheat oven to 375 degrees. Grease a cookie sheet.
Sift all the dry ingredients together and place in the bowl of an electric mixer. (You may also mix by hand.) Turn the mixer to slow speed and add the cubed butter. Mix until mixture resembles a coarse meal, about 3 minutes. Add the peaches and milk and mix just until ingredients are incorporated, 5 to 10 seconds. Do not overmix, or the dough will get tough.
Using a small ice cream scoop or spoon, scoop balls of dough about 2 inches in diameter and place 3 inches apart on prepared cookie sheet.
Bake until the tops of the scones are firm but not hard and the edges are golden, 15 to 20 minutes.
Five minutes before the scones are done, beat the powdered sugar and passion fruit syrup in a small saucepan until sugar is completely dissolved. Warm the glaze over low heat and drizzle onto the scones as soon as they come out of the oven.