01 -
Generously grease with vegetable shortening and flour the bundt pan. Ensure it is well-coated to prevent sticking. Use a 10-inch bundt pan or smaller, but avoid filling more than ⅔ full.
02 -
Melt ½ stick (¼ cup) of unsalted butter. Pour the melted butter into the prepared bundt pan. Sprinkle evenly with 1 cup of packed light brown sugar.
03 -
Thaw frozen peach slices if needed. Lightly blot the slices with napkins or paper towels to remove excess moisture. Arrange the peach slices in a single layer over the brown sugar in the bundt pan. For thick slices, split in half if needed. Finely chop ½ cup of leftover slices for folding into the batter (optional).
04 -
Preheat oven to 325°F (160°C). Sift the cake mix into a mixing bowl. Add instant vanilla pudding mix, eggs, brown sugar, flour, sour cream, water, vegetable oil, cinnamon, and vanilla extract. Mix at medium speed for one minute. Scrape the sides and bottom of the bowl, then mix for an additional minute. Fold in ½ cup of finely chopped peaches, if using.
05 -
Carefully pour or scoop the batter into the bundt pan, covering the brown sugar and peach slices. Avoid overfilling the pan. Bake for 55-60 minutes, or until the cake springs back when lightly touched and a toothpick inserted comes out clean or with a few crumbs. Check for doneness starting at 55 minutes.
06 -
Allow the cake to cool in the pan for 10 minutes. Place a serving plate or pedestal over the bundt pan. Use dish towels or oven mitts to invert the pan and carefully flip the cake out. Let the pan remain upside down for 1-2 minutes to allow any glaze to drip down. Some brown sugar may remain in the pan, which is normal.
07 -
Serve the cake warm or cool. If not serving immediately, refrigerate the cake and remove it from the refrigerator 2-3 hours before serving.