First you’ll want to lightly grease a 13×9 pan.
Mix cake mix according to package directions (or recipe if you’re making a from scratch cake) and divide the batter equally into 3 bowls (about 1 ½ cups of cake batter in each)
Add yellow food coloring to one of the bowls, add a few drops and stir until well mixed, adding additioan coloring if desired.
Repeat with the orange food coloring in the second bowl.
Leave the third bowl white.
Pour the yellow batter across the bottom of your prepared pan and spread evenly. Place in the freezer on a level surface for 20 minutes.
Remove the pan from the freezer and pour the orange batter across the yellow layer and spread it evenly. Place the pan back in the freezer for another 20 minutes.
Remove from the freezer and spread the final white layer evenly across the top. Allow the pan of layered cake batter to sit at room temperature for about 30 minutes while your oven preheats.
Preheat your oven to 350.
Bake according to package or recipe directions.
While the cake is still warm use a chopstick, straw, or handle of a wooden spoon to poke holes in even rows about an inch apart all over the cake.
Pour the sweetened condensed milk evenly over the top of the cake making sure to pour it into all the holes
Cover the cake with plastic wrap or aluminum foil and place in in the refrigerator at least 8 hours or overnight.