Preheat the oven to 375° Fahrenheit. Make the strawberry reduction first so that it has time to cool before use. In a small saucepan, combine water and sugar and bring to a simmer on medium heat. While that's heating up, blitz up the strawberries in a nutribullet or blender. Once the water + sugar has simmered for a few minutes, add in the blended strawberries and the balsamic vinegar and continue to cook for 10 minutes or until it has thickened to a jammy consistency. Take off the head and use a spatula to scrape into a heat-proof bowl. Let cool at room temp or in the fridge while you make the rest.

Grease a cookie sheet (15x10x1 inches) and line with parchment paper. Grease the parchment paper and be sure the corners are pushed in; set aside. Separate the eggs into two medium bowls (be sure that the whites are in a clean, dry bowl). In the egg yolk bowl, use an electric mixer to beat together the yolks, 1/3 cup of the sugar, the salt and the vanilla. Add in the flour and mix with a spatula to combine. Clean and dry the beaters of the electric mixer and then use them again to beat the egg whites on high until soft peaks form. Add in the remaining 1/3 cup of sugar and continue to beat until stiff peaks form. Using the spatula, carefully fold in 1/3 of the egg whites at a time into the rest of the cake batter until fully combined. Do not over mix or stir.

Pour cake batter into the greased pan and use the spatula to spread and even out the cake. Bake for 12-15 minutes until dry to the touch but not too golden. Remove from oven and let cool a few minutes before rolling it. The key is to roll a Swiss roll cake nearly immediately so that it cools in the final shape. Use a damp kitchen towel, along with the parchment paper already under the cake, to roll the cake short end to short end, so that the parchment paper and towel are rolled up in the cake. Let it sit rolled up until completely cooled.

While the cake is cooling, make the whipped cream. Using your electric mixer, beat the heavy cream on high until soft peaks form. Add in the powdered sugar and vanilla and continue beating until stiff peaks form.

Once the cake is cooled, carefully unroll and remove the towel. You can either spread the strawberry jam or whipped cream on the cake first, however you want your spiral to look. I usually spread the whipped cream first, making sure to not have too thick of a layer (or your cake will squish out the excess cream). I then spread the strawberry jam (stir it first, if it's too thick to spread, add a touch of water) over the cream layer evenly.  Once the filling is on, carefully roll the cake back up, short end to short end, being sure to roll tightly but not squishing out the filling. If you're serving later, I recommend wrapping the cake back up in the parchment paper and freezing for 30 minutes to an hour (or overnight), and then removing from the freezer 45 minutes before serving to slice it (it will slice very neatly if it's still slightly frozen).

You can also serve as a whole cake, topped with extra cream and strawberries - presentation is up to you!