Preheat oven to 350 degrees. Grease and flour a 9x13-inch baking pan.
Sift flour and baking powder together; set aside. Cream butter and sugar together until fluffy. Add eggs and vanilla, beat well. Add the flour mixture to the butter mixture bit by bit. Mix until blended.
Bake at 350 degrees for 30 minutes. Let cool.
Pierce Cake several times with a fork.
Combine the whole milk, evaporated milk and sweetened condensed milk. Pour enough over the cake to soak.
Frost with sweetened whipped cream. Top with strawberries and blackberries.
You can also buy white cake mix and prepare as directed on box in a 9x13-inch baking pan.