Step 1: Prepare the Oven and Pan: Preheat the oven to 350F (175C). Grease and flour a 9x13 inch baking pan. This prevents the cake from sticking and ensures easy removal. Alternatively, the pan can be lined with parchment paper, leaving an overhang to lift the cake out easily.
Step 2: Mix the Batter: In a large bowl, combine the cake mix, melted butter, eggs, milk, and vanilla extract. Mix using an electric mixer on medium speed until the batter is smooth and well combined, about 2-3 minutes. Be careful not to overmix, as this can result in a tough cake.
Step 3: Layer the Peaches: Pour the cake batter into the prepared baking pan, spreading it evenly. Arrange the sliced peaches on top of the batter in a decorative pattern or a uniform layer. The peaches should be close together but not overlapping excessively to ensure even baking.
Step 4: Sprinkle with Sugar and Cinnamon (Optional): In a small bowl, mix together the granulated sugar and cinnamon (if using). Sprinkle this mixture evenly over the peaches. The sugar will caramelize during baking, adding a delightful sweetness and slight crispness to the top.
Step 5: Bake the Cake: Bake in the preheated oven for 35-40 minutes, or until a wooden skewer inserted into the center of the cake comes out clean. The cake should be golden brown and the peaches should be tender.
Step 6: Cool and Serve: Remove the cake from the oven and let it cool in the pan for at least 15-20 minutes before slicing and serving. Dust with powdered sugar before serving, if desired. The cake is delicious served warm or at room temperature.
Optional Tips:
For a richer flavor, substitute melted butter with melted coconut oil.
Add 1/2 cup of chopped pecans or walnuts to the batter for added texture.
For a streusel topping, combine 1/2 cup flour, 1/4 cup sugar, and 1/4 cup cold butter (cut into small pieces). Crumble with your fingers and sprinkle over the peaches before baking.
Other fruits like nectarines, plums, or berries can be substituted for the peaches.