Once the cake is cool, make the whipped cream and prep the strawberries. Place the sliced strawberries in a medium sized bowl with the sugar and stir to combine. Cover and set aside. Beat the heavy cream in a stand mixer fitted with the whisk attachment until soft peaks form and the whipped cream holds its shape. Add the vanilla extract and mix well. When ready to serve, spoon the whipped cream over the top of the cake and top with the strawberries!