Preheat the oven to 350°F (175°C) and spray a 9x13-inch baking dish with non-stick baking spray.

In a large bowl, whisk together the lemon cake mix, 1 cup whole milk, lemon juice, canola oil, and egg yolks and whites until smooth and well combined.

Pour the batter into the prepared baking dish, spreading it out evenly.

In another large bowl, combine the sugar, instant lemon pudding mixes, 2 cups milk, and 1 ¼ cups cold water. Whisk for about 2 minutes until the mixture is thickened and well combined.

Spoon dollops of the pudding mixture evenly over the top of the cake batter.

Place the baking dish on a cookie sheet (to catch any drips) and then place it in the preheated oven. Bake for 50-60 minutes, or until a toothpick inserted into the center of the cake comes out clean.

Allow the cake to cool for about 30 minutes before serving. Dust with powdered sugar, top with lemon zest, and serve each piece with whipped cream, a slice of lemon, and a sprig of fresh mint.