Once cake is baked and allowed to cool for 10-15 minutes, use a toothpick or fork to poke holes all over the cake. A little bit at a time, pour milk mixture over the cake, allowing it to soak in before pouring additional mix. Continue until all milk is poured and soaked in.
Use other half of the heavy cream to make whipped cream; mix powdered sugar in slowly as you beat heavy cream in another large bowl with an electric mixer on high speed. Beat until soft peaks form on beaters.