1. Preheat oven to 350°F (175°C). Lightly spray a 9x13-inch baking pan with cooking spray.
2. In a large mixing bowl, blend together the cake mix, eggs, oil, peach nectar, and food coloring (if using) until well combined. Fold in the chopped peaches.
3. Turn the batter into the prepared pan. Bake for about 28 minutes, or until done. Check with a toothpick; it should come out without batter clinging to it, but moist crumbs are fine.
4. Allow the cake to cool in the pan.
5. For the frosting, combine butter, cream, and brown sugar in a saucepan. Bring to a boil, stirring constantly. Remove from heat and add vanilla extract and sifted confectioner's sugar. Whisk until smooth. Put back on low heat if necessary.
6. Pour the frosting over the cooled cake, aiming to coat it evenly on the first try as the frosting sets quickly.
7. Let the frosting harden at room temperature or in the refrigerator before cutting. Slice and serve.
Enjoy your delicious Brown Sugar Peach Cake!