Preheat oven to 400 F. Spray 15.5 x 10.5 in jelly roll pan with cooking spray. Line with parchment paper. Spray parchment paper with cooking spray and lightly flour it. Set a side.
In a bowl sift cake flour, salt, baking soda and matcha powder. Set a side.
Beat egg whites with an electric mixer to stiff peaks. Set a side, or keep in the fridge.
In a different bowl beat egg yolks and sugar until pale and frothy. Add vanilla and milk, whisk until combined.
Slowly add in dry ingredients, use a rubber spatula and mix until incorporated. Do not over mix.
Add egg whites in 3 additions. Gently fold them into the mixture.
Pour batter into prepared pan. Spread it into an even layer.
Bake for 10 minutes, until cake springs back to touch. Remove from oven and run a knife around the edges, to loosen cake.
Place a clean kitchen towel on your plot and generously sift powdered sugar over it.
Invert cake onto kitchen towel and remove parchment paper. Discard paper.
Gently roll cake and towel into a log. Let cake cool to room temperature.
In the mean time prepare filling:
Beat heavy cream with 1 Tbsp powdered sugar until stiff peaks.
In a bowl mix together mascarpone and the rest of the powdered sugar. (add more sugar according to your taste).
Using a rubber spatula, fold whipped cream into sugar mascarpone mixture. Add lemon zest. If the cream is not sweet enough, add more powdered sugar.
Once the cake has cooled, carefully unroll it. Spread the filling and roll cake back into a log.
Cover and refrigerate for at least 30 minutes, before you slice and serve it. Dust top of cake roll with powdered sugar.