01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish thoroughly.
02 - Spread lemon pie filling evenly across the bottom of the prepared baking dish.
03 - Scatter mandarin orange segments over the lemon filling and sprinkle with lemon zest.
04 - Sprinkle dry yellow cake mix evenly over the fruit layer. Do not stir or mix.
05 - Drizzle melted butter and milk evenly over the cake mix, covering as much dry mix as possible. Sprinkle with additional sugar if desired.
06 - Bake for 35-40 minutes until the top is golden brown and edges are bubbling.
07 - Let cool for at least 15 minutes before serving. Serve warm with whipped cream or vanilla ice cream if desired.