Preheat oven to 350F
Line a 15x8 jelly roll pan with parchment paper.
In a large bowl of a stand mixer beat egg whites until soft peaks form. Set aside.
In another large bowl of a stand mixer whip butter with monkfruit and egg yolks until creamy.
Add in the vanilla extract and chocolate syrup. Mix well.
Lastly, mix in the flours and baking soda. Mix until incorporated. Do not overmix.
Fold beaten egg whites carefully so they stay fluffy.
Spread batter into parchment lined jelly roll pan evenly.
Bake 25 minutes THEN loosely place foil on top and bake and additional 8-10 minutes until toothpick tested clean.
Cool 5 minutes then flip over onto a flat board or pan bottom, parchment side up.
Now cover with a damp towel for 5 minutes to loosen the parchment paper.
Gently peel off the parchment paper. Now spread the towel out over the top side. Put a pan bottom or flat cutting board over the towel and flip over. Now the towel should be UNDER the cake.
Slowly start rolling the cake up in the towel like this.
It should look like this now. Cool completely.
After cool, unroll onto a flat surface THEN place a plastic wrap covered board over it. FLIP so the plastic wrap is underneath the cake. It may crack, it may not. It depends on the temperature of your home. When the filling is spread on it will come together.
Now put all of the filling into the middle of the cake like this.
Spread evenly and leave a 1-2 inch border around.
Should look like this.
Now slowly roll it up keeping the plastic on the outside. Only use it as a guide, do not roll it up in the cake roll. It should look like this when you are done.
Now you will put in the fridge overnight or 8 hours minimum.
Once you are ready to serve it or right before taking to your event, place the roll on a platter or 9x13 glass pan.
Make ganache and once smooth and mixed pour over cold cake roll. It will solidify and set like this.
Optionally you can drizzle some chocolate syrup over it all for decoration. Do not keep at room temperature any longer then a hour as it will start to melt and collapse.
It will keep up to 5 days in the fridge covered airtight.