Lets macerate the berries! You can double this if you want extra berry in the cake. Place frozen raspberries(or fresh), in a medium sized bowl. Sprinkle over sugar and pour over rum. Mix gently to combine. Cover and let sit to turn into a beautiful red syrup while you prepare the cake.

Preheat oven to 340 F/170 C. This isn't a deal breaker- but egg whites whip up nicer when they're at room temperature, so you should take them out some minutes before beginning. Add 4 egg whites to the bowl of a stand mixer fitted with the whisk attachment(or use an electric hand held whisk). Beat them for about 2 minutes, until they are at soft peaks(starting to hold together).

With the mixer running on medium-low, gradually sprinkle in the sugar, over the course of 30 seconds. Never add it all in at once! Once the sugar is in, continue to whisk for another 30sec-1 minute, until stiff peaks form. That means when you pull out the whisk, the tip should stay standing and not fall over, like in the photo.

Add in the egg yolks and 1/2 cup flour. Using a spatula, gently combine the batter, scooping till the bottom of the bowl and up and over the top(this is called a fold). Continue until the batter is combined and there are no more yellow streaks(about 20 folds).

Place a baking sheet on a baking tray(12x17 inch), and gently pour out the batter, spreading it almost to the edges of the pan. Place in the oven to bake for 17 minutes. Take the cake out of the oven and flip it out onto a kitchen towel. Peel off the parchment, and roll the cake up in the towel- this keeps its shape in a roll while it cools.

Wash the bowl after making the cake, and dry it. Add the whipping cream and whip till it starts to hold together(a minute or two). Slowly add the 1/2 cup sugar with the mixer running, and the pudding mix. Mix for another minute or minute and a half on medium/high speed. Be careful not to over mix or the cream will separate.

Unroll the cake from the towel, and spread over the cream. Arrange the sugared raspberries on top, drizzle over some or all of the juices. Roll the cake up lengthwise, and place on a serving tray. Before serving and slicing, dust lightly with powdered sugar, if desired. Enjoy!

To keep, wrap tightly in Saran Wrap and place in the fridge for 2-3 days.