Preheat your oven to 375°F (190°C).
Line the baking pan with parchment paper.
Grease the paper lightly with butter.
This prevents sticking later.
Beat eggs and sugar until fluffy.
This takes about 3 minutes.
Add vanilla extract and mix well.
Sift flour, cocoa, baking powder, and salt.
Fold dry ingredients into egg mixture gently.
Don't overmix the batter.
Pour batter into prepared pan evenly.
Bake for 12-15 minutes until springy.
Don't overbake or it will crack.
The cake should be soft and moist.
Dust a clean towel with powdered sugar.
Turn hot cake onto the towel immediately.
Peel off parchment paper carefully.
Roll cake with towel from short end.
Let it cool completely in rolled position.
Whip heavy cream until soft peaks form.
Add powdered sugar and vanilla extract.
Beat until stiff peaks appear.
Keep it cold until ready to use.
Unroll the cooled cake gently.
Spread cream filling evenly on cake.
Leave 1 inch border on edges.
Roll cake again without the towel.
Wrap in plastic and refrigerate 30 minutes.
Beat butter until smooth and creamy.
Add powdered sugar and cocoa powder gradually.
Add milk and beat until fluffy.
The frosting should spread easily.
Place rolled cake on serving plate.
Spread chocolate frosting all over the cake.
Use a fork to create bark texture.
Drag fork lines along the log.
Add powdered sugar for snow effect.
Refrigerate until serving time.