Make the tres leches cake by following the recipe for Easy Tres Leche Cake.
Pour the batter between two 8-inch square cake pans and bake for roughly 30-35 minutes.
Mix together the 3 kinds of milk and pour the mixture evenly over the 2 cakes. Cover and allow to soak overnight.
The next day, whip the cream to stiff peaks.
In a medium mixing bowl, combine the blueberries, raspberries, and strawberries.
Place one layer of the tres leches cake on a serving plate and drizzle on any liquid left in the pan.
Spread some whipped cream over the cake and cover with half the berries.
Carefully place the second cake layer on top.
Spread another big dollop of whipped cream on top of the second layer and spread the remaining whipped cream on the sides of the cake. It will be a rustic, naked cake look.
Top the cake with the remaining berries and serve immediately or chill (for no longer than 4 hours) until ready to serve.
This cake is best served the day it is made but you can store any leftovers in an airtight container in the refrigerator for up to one day.