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 dish.
03 - Distribute mandarin orange segments over the lemon filling. Sprinkle lemon zest evenly across the top.
04 - Sprinkle the dry yellow cake mix over the fruit layer in an even layer. Do not stir or mix.
05 - Drizzle melted butter and milk evenly over the cake mix, ensuring coverage of as much dry mix as possible. Optionally sprinkle granulated sugar on top.
06 - Bake for 35-40 minutes until the top is golden brown and the edges are actively bubbling.
07 - Allow to cool for at least 15 minutes before serving. Serve warm, optionally garnished with whipped cream or vanilla ice cream.