Prepare Cereal Milk:

1. In a bowl, combine the plant-based milk and cereal. Let it sit for about 10-15 minutes to infuse the milk with cereal flavor. Strain the mixture through a fine-mesh sieve, pressing the cereal to extract as much liquid as possible. Discard the cereal solids. You should have about 1 cup of cereal-infused milk.

Prepare the Cake:

1. In a mixing bowl, whisk together the flour, baking powder, baking soda, and salt.
2. In another bowl, whisk together the granulated sugar, vegetable oil, apple cider vinegar, and vanilla extract until well combined.
3. Gradually add the dry ingredients to the wet ingredients, alternating with the cereal milk, starting and ending with the dry ingredients. Mix until smooth and well combined.

Bake the Cake:

1. Pour the batter into the prepared baking dish or cake pan, spreading it evenly.
2. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
3. Remove from the oven and let the cake cool completely in the pan.

Prepare the Tres Leches Mixture:

1. In a bowl, whisk together the sweetened condensed coconut milk and canned coconut milk until smooth.

Soak the Cake:

1. Once the cake has cooled, use a fork or toothpick to poke holes all over the top of the cake.
2. Slowly pour the Tres Leches mixture over the cake, allowing it to absorb. You may not need to use all of the mixture; stop when the cake is soaked but not overly soggy. Let the cake sit for 30 minutes to absorb the liquid.

Chill and Serve:

1. Cover the cake and refrigerate for at least 2 hours, or preferably overnight, to allow the flavors to meld and the cake to fully absorb the Tres Leches mixture.
2. Before serving, optionally top with vegan whipped cream and fresh berries or fruit slices.