Apply a thin layer of butter (not from ingredients) on the inside of the Baking tray, then place a baking paper at the bottom which goes slightly above the edges.

*If using baking paper, be sure that it does not touch the insides of the oven.
 

Put the egg whites in a large bowl, and beat until it forms stiff peaks.

Slowly add half of the sugar and continue beating.

<Important Point>
The point is to have the egg whites beaten. 
 

Add the remainder of the sugar to the yolks, and warm both with hot water.
Remove when it reaches body temperature and beat until It is white and some lines start to appear (mayonaise-like consistency).
 

Preheat the oven (Do not put the cooking accessories or food inside).

Select MANUAL MICRO, CONVEC OVEN and press ENTER.

Choose 1 TRAY, PREHEAT, press ENTER.

Select 170°C then press START.

Combine the egg whites with the yolks and mix with a whisk until smooth.
 

Add the flour and cocoa by shifting into step 5 in order not to break bubbles and mix by bringing the batter from the bottom until you see no traces of flour.
In doing so, as a guideline, move the spatula a little and mix it swiftly so that the powder does not disappear, and if you scoop up the batter with a spatula, it falls like a ribbon, leaving marks for a while.
*Compared to sponge cake, roll cake has a lower cake flour to egg ratio. The texture will be course. if scarce flour is used. Also but be careful of the dough becoming sticky.
Quickly add vanilla extract and milk, then mix.
 

Pour the batter into the Baking tray from step 1, smoothing out the surface and removing air.
 

When preheating is complete, put the Baking tray prepared in step 7 in the oven. 
Set the knob to 18 - 20 MINUTES and press START .
 

After cooking, leave step 7 on the baking paper and take it out from the Baking tray and let it cool down.
 

Making whip cream. Put chilled whip cream and sugar in bowls.
Beat while cooling each bowl, adding vanilla extract and beat more until the cream becomes thick.
Beat until some lines start to appear. Mix the chunks of fruit.
 

Turn the cake over, removing the baking paper.
Turn it back over again, placing it on the baking paper, spread on cream and roll.
    

*If you are worried about the hardness of the outer circumference, touching the hard parts with a damp cloth will make it easier to roll

*By diagonally cutting the cake at the end of the roll by 1cm it will rest nicely with no overlap at the edge. 
 

After it is rolled, wrap it in baking paper, and further wrap in plastic.
Place the rolled end down in a refrigerated room and let it adjust for about 30 minutes.

＊When baking 2 rolls, after preheating to 170°C with CONVEC OVEN/2 tray/ PREHEAT, place the Baking trays on each upper and lower position, and bake for 25-27 minutes. If you are worried about uneven baking, change the shelf position and orientation of the Baking trays when the remaining time is between 8 and 10 minutes.