Creating the Brown Sugar Peach Layer Cake can be straightforward if you follow these simple steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Grease and flour three 9-inch round cake pans.
2. Mix Dry Ingredients: In a medium bowl, sift together the flour, baking powder, salt, and cinnamon (if using).
3. Cream Butter and Sugar: In a large mixing bowl, cream the softened butter and brown sugar until light and fluffy.
4. Add Eggs and Vanilla: Beat in the eggs one at a time, then stir in the vanilla extract until well combined.
5. Combine Wet and Dry Ingredients: Gradually add the dry ingredients to the wet mixture, alternating with the milk. Mix until just combined.
6. Fold in Peaches: Gently fold in the diced peaches, being careful not to overmix.
7. Divide Batter: Evenly pour the batter into the prepared cake pans.
8. Bake: Place in the oven and bake for 30-40 minutes, or until a toothpick inserted in the center comes out clean.
9. Cool: Remove from the oven and allow the cakes to cool in their pans for 20-30 minutes. Then, gently transfer them to wire racks to cool completely.
10. Prepare Frosting (optional): While the cakes cool, you can prepare a simple frosting using powdered sugar, butter, and a splash of milk.
11. Assemble the Cake: Once the layers are completely cool, place one layer on a serving platter. Spread frosting on top, add the next layer, and repeat until all layers are stacked.
12. Dust with Powdered Sugar: For an elegant touch, dust the top of the cake with powdered sugar before serving.

These steps will guide you in creating this incredible cake effortlessly.