Preheat the oven to 350 degrees F and coat inside of a 9-inch x 13inch baking dish with non-stick cooking spray.
Prepare cake batter according to the package directions. Stir in the maple syrup and lemon juice.
Pour cake batter into the prepared baking dish and bake according to the package directions.
Once the cake is done cooking, poke round holes into the cake every inch or so with the back of a spoon or cooking utensil. Set aside. (The holes should be about 1/4-inch in diameter and go nearly to the bottom of the cake.)
Prepare the blue Jello by adding 1/2 cup of boiling water to the Jello mix in a bowl. Stir together until the jello dissolves. Repeat with the red Jello in a separate bowl.
With a spoon, pour each jello color into separate holes on the cake, making sure the colors don’t mix. DO NOT overfill the holes. Alternate between colors and holes to create a fun variation in colors.
Place cake in the refrigerator for 30 minutes to cool.
In the meantime, use a stand mixer or hand mixer to beat the heavy cream, powdered sugar, and vanilla together until stiff peaks form.
Once the cake is cool, spread the whipped cream over the cake. Top with sprinkles and then cut into 12 slices before serving.
If you want to use fruit on top instead of sprinkles go ahead! You can use blueberries and halved strawberries to make a flag design or just place them around the top of the cake any way you like.You can store this cake for 3-4 covered in the fridge.This cake also freezes well. Freeze the cake in the pan before adding the whipped cream topping. Store for up to 2 months. Thaw in the fridge overnight before topping with whipped cream and serving. (If you want to top the cake before freezing swap out for Cool Whip.)