Preheat your oven to 375. Find a 10 x 18 (or similar) baking sheet with sides. We used a quarter size cookie sheet. Line it with parchment paper and spray with a flour based baking spray for good measure.
Dust your clean tea towel with powdered sugar and set aside.
In a standing mixer, whip 3 egg whites medium speed until frothy. Slowly add 1/4c. of you 1 cup sugar. Whip on high until stiff peaks form. Set aside.
In another bowl beat 2 whole eggs and the three yolks from your separated eggs for 2 min. Slowly add the remaining 3/4 cup of sugar, water and vanilla.
Sift together flour, salt baking powder and then add slowly to your second egg mixture until just combined. Do not over mix.
Remove bowl from mixer, and hand fold in your egg whites.
Spread some rainbow sprinkles on to your lined baking sheet. Then spoon batter on to sheet and smooth evenly. Bake at 375 for 11-13 min.
Immediately turn cake onto sugared tea towel. Peel off old parchment and add a new sheet to the top. Now quickly roll the cake up with the tea towel, from the shorter end. Let cool in towel for at least 1 hour.
While it cools, whip cream cheese until soft with an electric mixer. Slowly add heavy whipping cream. Once it begins to thicken, slowly add sugar and vanilla. Refrigerate for later.
Once your cake has cooled for at least an hour, the fun part can begin.
Gently unroll your cake. You can spread a layer of fruit preserves on it if you like. Make sure to get all the way to the edges. Next you can add a layer of your cream. Keep it pretty thin, remember this has to roll back up.
Following that, you can add rows of fruit, pressed into the cream! Throw in some sprinkles for good measure. It is a rainbow after all.
Prepare a large piece of plastic wrap and have it ready on the counter because now it is time to carefully re-roll your cake. Be gentle so you don’t squish all your fillings right out the sides. Wrap tightly in plastic wrap and refrigerate, seam side down, for at least three hours. Even better if you leave it over night.
Slice gently and enjoy your rainbow roll up.