Pour batter into prepared cake pan. Bake for 30-35 minutes until the cake springs back when slightly touched and a skewer inserted into the center comes out clean. Allow cake to cool on a wire rack for 15 minutes.
While the cake is till warm, poke lots of holes in the cake with a fork or toothpick. Pour the milk mixture over the cake slowly and gradually, allowing it to soak in. Refrigerate for 12 hours (can be less but it will taste better this way).
Before serving, make the whipped cream frosting: In the bowl of an electric mixer fitted with the whisk attachment, whisk heavy cream, powdered sugar, and vanilla on high speed until stiff peaks form and frosting is thick. Use immediately to frost cake. Top with fresh fruit, if desired.