Sponge cake:

Cup of Yum
1. Separate the egg yolks and egg whites for 4 of the 5 eggs. Place the egg whites is a large mixing bowl at room temperature.
2. Pre-heat oven to 400 F (200 C) degrees.
3. Use an electric mixer to mix the 4 egg yolks with the sugar and vanilla extract. Add the whole 5th egg and continue mixing for 3 more minutes (or until the mixture is creamy and has doubled in size).
4. Use a mixing spoon or spatula to slowly add the flour to the creamy egg yolk mix.
5. Beat the egg whites until stiff peaks form, use a mixing spoon to gently fold the beaten egg whites in to the egg yolk and flour batter.
6. Place a sheet of parchment paper on a large rectangular metal baking sheet, or if you have one, a silicone jelly roll sheet. You can spray the parchment paper or jelly roll sheet with baking spray. Spread the cake mix on the rectangle surface, keeping a little over half an inch of thickness across the area.
7. Bake in a pre-heated oven for 10 minutes at 400 F (200 C) degrees.
8. Take the cake out and cover it with a slightly damp clean kitchen towel for 5 to 10 minutes. At this point, carefully detach the cake from the parchment paper or jelly roll pan.
9. Pre-roll the cake while wrapped in the kitchen towel. Let it rest rolled in the kitchen towel until it cools down.

Coffee buttercream filling (can be made ahead of time):

1. Make a simple syrup by melting the sugar and water in a pan over medium heat until the sugar is fully dissolved, stir as needed.
2. Use an electric mixer to beat the egg yolks in a bowl, and slowly add the hot sugar syrup. Do this slowly and continue mixing until you have a thick and creamy light-yellow mix, about 5 minutes.
3. Add in the softened butter and continue mixing until you have shiny and creamy consistency.
4. Add the instant coffee liquid syrup and continue mixing with the electric handheld mixer until you have a very smooth and shiny thick creamy mix. If you find the cream is not thick enough, place it in the fridge for 15 minutes, the mix again. This coffee buttercream filling can be made a day in advance and any extra can also be frozen for future use.

For the chocolate frosting:

1. Use a water bath or double boiler over low heat to melt the chocolate with the butter and cream. Keep the heat on simmer and stir constantly until melted.
2. Remove from the heat and let it cool down until it starts to thicken. Mix it with a spatula.

For the Christmas log assembly:

1. Remove the towel from the sponge cake and gently unroll it.
2. Spread the coffee buttercream uniformly on top of the cake. Make it as thick as possible and use it entirely.
3. Roll the cake length-wise by taking the shorter side and gently rolling it across the length of the cake. Do not press, and do not worry too much about the edges being non-uniform at this point.

Decorating the Christmas log:

1. Gently spread the chocolate frosting using a spoon or flat spatula to cover cake roll.
2. Refrigerate for about an hour to let the icing solidify.
3. Next, use a sharp knife to cut the edges of the rolled cake to make them clean and straight. Do all this on a “draft” plate or on top of parchment paper, which will be full of chocolate icing drippings.
4. Once the cake is all finished you can lift it and transfer it to the plate you’ll use for presentation and final serving.
5. You can also use the end of a chopstick to very lightly carve the chocolate cream into a wood log like texture, without removing it entirely. Be very gentle.
6. Decorate with candied cherries or fresh berries or green/red soft candies, cake sprinkles, mint leaves, etc
7. Refrigerate if not serving immediately but bring it back to room temperature to serve.