In a medium pot, heat the condensed milk and heavy cream on medium heat. Stir until they're well blended.

In the meantime, mix the whole milk with the cornstarch in a small bowl and add it to the pot. Mix well and simmer for a few minutes until it comes to a boil. Remove from the stove once the mixture has thickened.

Place a layer of crackers at the bottom of the baking dish. Then, pour one layer of the milk mixture over the crackers, followed by a layer of Milo. The amount of Milo sprinkled on top of the mixture depends on each person's taste. Continue with this process until you run out of the milk mixture, making sure you finish with a layer of Milo.

Cover the dessert with plastic wrap and refrigerate it overnight so the milk can set before serving.