1. Preheat oven to 350°F (176°C) and prepare a 9×13 inch cake pan with non-stick baking spray.
2. Add the flour, sugar, baking powder and salt to a large mixer bowl and combine. Set aside.
3. Add the milk, vegetable oil, vanilla extract, eggs and orange zest to a medium sized bowl and combine.
4. Add the wet ingredients to the dry ingredients and beat until well combined.
5. Slowly add the water and orange juice to the batter and mix on low speed until well combined. Scrape down the sides of the bowl as needed to make sure everything is well combined.
6. Pour the batter into the prepared cake pan and bake for 28-30 minutes, or until a toothpick comes out with a few moist crumbs.
7. Remove the cake from the oven and poke holes all over the top of the cake.
8. Add the JELLO powder to the boiling water, then stir until the powder dissolves completely. You don’t want it to remain grainy.
9. Add the orange mixture to the sweetened condensed milk and mix until well combined.
10. Pour the orange mixture over the top of the cake, allowing it to soak into the holes. Let cake cool completely.
11. To make the whipped cream topping, place the heavy whipping cream, powdered sugar and vanilla extract into a large mixer bowl. Whip on high speed until stiff peaks form.
12. Spread the whipped cream over the top of the cake and top with swirls of frosting and orange candy slices.
13. Refrigerate the cake until ready to serve. Cake is best for 3-4 days.
* Be sure to use a fresh orange for the juice, not store-bought juice. Store-bought juice has additional sugar and other things added that will affect the way the cake bakes.