Make the Cake:
Preheat your oven to 350°F (175°C). Grease and flour a 9x13-inch baking pan or line it with parchment paper.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
In a large bowl, cream the butter, granulated sugar, and brown sugar until light and fluffy using an electric mixer.
Add eggs one at a time, beating well after each addition. Stir in vanilla extract and almond extract (if using).
Gradually mix in the dry ingredients, alternating with the buttermilk, starting and ending with the dry ingredients. Mix until just combined.
Gently fold in the diced peaches.
Pour the batter into the prepared pan and spread evenly. Bake for 40–45 minutes or until a toothpick inserted in the center comes out clean.
Let the cake cool completely on a wire rack before frosting.
Make the Brown Sugar Frosting:
In a saucepan, melt the butter over medium heat. Add the brown sugar and heavy cream, stirring constantly, and bring the mixture to a gentle boil. Cook for 1–2 minutes.
Remove the saucepan from the heat and let the mixture cool slightly.
Gradually whisk in the powdered sugar, vanilla extract, and a pinch of salt until smooth and creamy. Add more cream if needed to reach your desired consistency.
Assemble the Cake:
Spread the brown sugar frosting evenly over the cooled cake.
Garnish with additional peach slices or a sprinkle of cinnamon if desired.
Slice, serve, and enjoy the fruity, caramelized goodness!