Preheat oven to 350 degrees F.
Grease and flour a bundt cake pan.
Combine the cake mix and peach flavored jello.
In a separate bowl, whisk together the oil, peach juice (or water), and eggs. Add into the cake mix and whisk together till smooth, about 3 minutes. Pour batter into prepared bundt pan, filling 3/4 of the way full. Bake for 35 to 40 minutes. Let cool for about 15 minutes and remove from pan, using a small knife to help loosen the edges. Let cool completely. While cooling, prepare the buttercream.
In the bowl of a stand mixer fitted with the paddle attachment, cream the butter till smooth. Add in the powdered sugar, vanilla, peach extract (if using), and milk. Mix on low till combined. Turn the mixer up to medium and continue to whip the frosting for a minute or so. Divide buttercream into 2 bowls.
Color one half of the buttercream bright yellow and the other half a deep orange (mostly orange with a hint of red). Frost half of the bundt cake with the yellow and the other half with the orange. First do a very thin crumb coat. Chill in the fridge for about 30 minutes. Then do a final coat of buttercream, careful to keep a defined line where the two colors meet. Place the cake on a baking sheet and begin covering the entire cake in a layer of clear sanding sugar. Tilt the cake slightly the get all the sides.