For the cake: Purchase any type of white cake mix and follow directions. Except instead of using oil use one stick butter.
For the pastry cream: Place the milk, half the sugar and the vanilla extract in a saucepan over medium heat. Then combine the egg yolks and the remaining sugar in a bowl and whisk until the color of mixture is light. Add in the flour and the salt, mix completely. When the milk just begins to boil, remove from heat. Very slowly pour the hot milk into the yolk mixture, stirring constantly. When about half of the milk has been added, place all of the yolk mixture into the saucepan over medium heat. Mix the pastry cream as it heats, making sure to reach all of the corners of the pan when you stir. Let boil for about 1 minute, stirring constantly until mixture is thick.
Remove from heat and add the butter. Place into a bowl and cover directly with plastic wrap to stop a skin from forming on the cream. Chill for about one hour.
Fruit Topping: By this time cake should be finished. Let cake cool for two hours. Slice bananas and strawberries.
Open the can of crushed pineapple and pour juice over strawberries and bananas.
For the whipped cream: Pour one cup of whipping cream in a bowl. Whip the cream until it is almost stiff. Then add sugar and vanilla extract. Beat until cream holds peaks.
To assemble: After cake is cooled for at least 2 hours, remove from pan and slice into two layers. Place one layer of cake on bottom of pan. Spread over half of the crushed pineapple over the botton of the cake. Then add a thin layer of pastry cream. Place the second half of the cake on top. Than layer with strawberries and bananas. Then drizzle chocolate over the fruits.
Top with whip cream when serving.