Bring the eggs to room temperature. Combine the flour and the leaves from 1 black tea teabag, and sift.
Place the remaining black tea leaves into a heat-resistant dish and add 2 tablespoons of water. Microwave for 30 seconds. Wrap the dish and let steam.
Strain Step 2 through a tea strainer. Combine 1 tablespoon of the tea liquid and butter. Heat using a hot water bath.
Add the eggs and sugar to the bowl and, while continuously heating on the hot water bath, whip until thickened. (Refer to １in Helpful Hints.)
Add the sifted powdered ingredients and use a rubber spatula to gently mix. Add Step 3 and mix together.
Pour into a baking sheet lined with parchment paper. Smooth the surface with a card. Without creating air bubbles, bake in a 200°C oven for about 8 minutes. (Please refer to 2 in Helpful Hints)
Remove from the baking sheet immediately (leave parchment paper in place) and cool on a rack. Cover with plastic wrap so the surface doesn't dry out.
Make the syrup. In a heat-resistant container, add the sugar and 2 tablespoons of water. Microwave and let the sugar dissolve. Once it has cooled, add the rum.
Make the white chocolate cream. Pour the heavy cream into a small saucepan and turn on the heat. When it begins to boil, remove from heat and add the shaved white chocolate. Heat until melted.
Transfer the white chocolate mixture from Step 9 to a bowl, and place it in another bowl filled with ice water. While cooling, whip until stiff peaks form.
Flip the cake upside down and gently remove the parchment paper. Place the browned side facing up and spread on the syrup from Step 8.
Diagonally cut the edge closest to you, which will be the ending edge of the roll. Spread on the cream from Step 10, leaving space about 3 cm from the ending edge. (There will be about 1/3 of leftover cream.)
Roll the cake and wrap with a sheet of parchment paper. Cool in the refrigerator for about 1 hour. (Refer to 3 in Helpful Hints)
Diagonally cut off the first 5 cm from the edge. Spread on the cream, and place the cut piece on top. Cover evenly with cream.
Stick on the white chocolate pieces and sprinkle some powdered sugar over cake. Once the decorations are in place, it's finished.
Story Behind this Recipe
I wanted to make a pure white Buche de Noel so I decorated it with white chocolate and white chocolate cream.
1. The water temperature should be 60°C. Once the egg mixture has warmed up to body temperature, remove from the hot water bath. Sufficiently whip until thick enough to be able to write words on its surface. 2. How to remove the air bubbles: gently hit the bottom of the baking sheet 2 to 3 times. 3. Make sure the edge of the rolled cake is facing down.