Preheat oven to 375°F. Line the bottom and sides of a 9-inch springform pan with greased parchment.
In a stand mixer, fitted with the paddle attachment, cream the butter, brown sugar, honey and vanilla on medium-high speed until light in color and texture, about 5 minutes.
Beat in the eggs on medium speed, one at a time, until incorporated.
In a bowl, whisk together the flours, baking powder and salt.
Add 1/3 of the flour mixture to the butter mixture and mix on low speed until incorporated. Add half the milk and mix until smooth. Repeat with another 1/3 flour mixture and remaining milk, then finish with the last of the flour. Mix just until incorporated.
Spread the batter into the prepared pan. Arrange the peaches on top of the batter, saving the peach half for the center.
Bake for about 1 hour 10 minutes or until a tester comes out clean. Allow to cool for 20 minutes before removing from pan.
Serve room temperature, dusted with confectioners' sugar.