Pre-heat oven to 350 degrees F. Line 11×17 jelly roll pan (rimmed cookie sheet) with parchment. 

Cake:

1. In large mixing bowl beat the eggs with whisk attachment until thick and pale in color. 
2. Add in the sugar and vanilla, mix until well combined and mixture leaves a trail in the bowl. 
3. In a medium bowl, sift the flour, cocoa, salt and baking powder. Fold dry ingredients into the batter. Batter will start out streaky, continue folding until mixture is completely combined. 
4. Mix the melted butter and milk in a bowl. 
5. With mixer on low slowly add the butter and milk mixture to the cake batter. Mix until just combined. 
6. Pour batter (batter is pourable) into prepared pan and spread with spatula so batter is evenly spread corner to corner. 
7. Bake until center of cake springs back when gently pushed on about 10-12 minutes.
8. Let cake cool 5 minutes. Loosen the edges of the cake by gently lifting up on the parchment at the corners. 
9. Using the parchment under the cake start rolling the cake up. Roll up from the long side, not the short side. This will give enough length to cut a side brach and top branch. 
10. Place rolled up cake, seem side down, onto a cooling rack and cool completely, about 60-90 minutes. (DO NOT cool overnight or cake will be too stiff and will break when you try to unroll it). 

Filling:

1. Place egg whites and sugar in a medium sauce pan. Whisk until warm and sugar has dissolved. This can be tested by rubbing a bit of egg white mixture between your fingers, if it is smooth with not sugar granuals it is ready. 
2. Let cool to room temperature. 
3. Once egg white mixture is at room temperature pour into mixing bowl fitted with a whisk attachment. Whisk until stiff peaks form. Stiff peaks are when the egg white mixture holds a peak and does not collapse on itself. 
4. On low speed, add in the butter, one stick at a time. Move mixer speed up to med-high and mix until buttercream forms. This may take a few minutes. It may look curdled for a minute, just keep mixing. 
5. Once buttercream is formed, add in the vanilla and mix to combine. 

Ganache Frosting:

1. Place chocolate and heavy cream in small sauce pan. 
2. Heat on low until mixture begins to melt. Once heavy cream is hot (but not boiling) remove from heat and stir with spatula. 
3. Stir in small circular motions, as ganache begins to form expand your stirring circles to the outer edge of the pan. Stir until completely combined and ganache is formed.

Mushrooms:

1. For the stems break pretzels into two pieces each. 
2. With sharp pairing knife, warm blade under hot water and wipe dry. In a gentle sawing motion cut the truffles in half, let the heat of the blade do the work.  
3. The center of the Lindt truffle is soft ganache, push pretzel into ganache to form the stem.
4. Set aside. Repeat with remaining mushrooms. 

Assembly:

1. Unroll cake. Spread filling onto the cake. Leave a 1/2 inch border on the outer edges as filling will be pressed to the edges as the cake is rolled back up. If inner edge keeps rolling back up do your best to spread filling under the fold. 
2. Roll cake back up without the parchment paper. Make sure it is set seem side down. Chill completely, about 2 hours minimum. 
3. Once cake is chilled place rolled cake onto platter. Cut one inch off each end of the rolled cake to give a clean look to each end. 
4. Cut a 4” piece at a 45 degree angle and position the angled edge against the side of the cake log to make a side branch. If there is a gap between the two rolls, fill with left over buttercream filling. 
5. Cut off the pointed edge, cut back about 2 inches and place this piece on top of the large cake roll to be your top branch. 
6. Pour warm (not hot) ganache over the log and spread into place with off set spatula. To coat the top branch, put ganache on spatula and spread in upward swipes until covered. 
7. Refrigerate 45 minutes to set the ganache. 
8. Arrange mushrooms around the Buche De Noel. 
9. Sprinkle with powdered sugar to make it look like snow.
10. Arrange sugared cranberries and orange peels around the cake in a decorative manner. 
11. Serve at room temperature. 
12. Store in airtight container or wrap in plastic wrap. Refrigerate.