Step 1: Prepare the Oven and Pan: Preheat the oven to 350F (175C). Grease and flour a 9x13 inch baking pan to prevent sticking.
Step 2: Combine Wet Ingredients: In a large mixing bowl, whisk together the vegetable oil, milk, eggs, vanilla extract, and reserved peach juice until well combined. Ensure all ingredients are fully incorporated.
Step 3: Incorporate Dry Ingredients: Gradually add the yellow cake mix to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix. Overmixing can result in a tough cake.
Step 4: Add Peaches: Gently fold in the drained peach slices into the batter. If desired, sprinkle the batter with ground cinnamon for added warmth and flavor.
Step 5: Bake the Cake: Pour the batter into the prepared baking pan and spread evenly. Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.
Step 6: Cool and Serve: Remove the cake from the oven and let it cool in the pan for 10-15 minutes before slicing and serving. Enjoy warm or at room temperature.
For a richer flavor, substitute melted butter for the vegetable oil. A sprinkle of almond extract can also enhance the peach flavor. Feel free to add a streusel topping for a crunchy texture.