Preheat oven to 350°F.: When the oven warms to 350°F , you will notice a gentle, dry heat that helps brown the top while allowing the filling to stew and bubble. This temperature is chosen so the syrup thickens without burning the edges too quickly. A common mistake is not preheating, which leads to uneven baking and a soggy topping, so wait until the oven reaches temperature before inserting the dish.
Spread peaches, with liquid, into a 9×13-inch baking dish.: The juices from the canned peaches will steam and reduce as they bake, creating a glossy, syrupy pool that feeds the topping. As you spread them, listen for the soft sliding sound of peaches moving in syrup, and watch how the liquid settles into an even layer, which ensures consistent bubbling. If you crowd the peaches into a deeper container, the filling may take longer to bubble and could lead to undercooked topping.
Sprinkle cake mix evenly over peaches.: An even dusting of dry cake mix allows the syrup to penetrate in places while other spots remain crisp. Visually, you want full coverage without clumps, so sprinkle in a slow, steady motion to avoid dense patches. If you dump the mix in one spot, it can clump and create gummy pockets instead of the intended crunchy contrast.
Place butter cuts evenly over the cake mix. Sprinkle with cinnamon.: The small slices of cold butter will sizzle and melt into the dry mix as the dish heats, forming golden islands that brown attractively. Arrange the butter so every area has some coverage, and finish with a light, even dusting of cinnamon to add aromatic warmth. If the butter is placed unevenly or too thin, you will end up with dry patches and inconsistent browning.
Bake for 40-45 minutes, until golden and bubbly. Serve warm or at room temperature.: As the cobbler bakes, the kitchen fills with the sweet, caramelizing scent of peach syrup and browned butter . Watch for the edges to bubble and the top to take on a deep golden color, those are signs the syrup has reduced and the topping is crisp. A common error is removing it too early; if the center has not begun to bubble, the texture will be looser and the cake mix may taste floury. Let the dish rest briefly so the juices settle before serving.