Bûche de Noël

It's called sponge cake because its flavor and moisture and intrigue comes from whatever syrup chosen to saturate it. Usually something with alcohol. Like a cake cocktail.

Chef John turns his to chocolate and bakes it in baking pan form.

The usual recipe baked in usual cake pans does not work in Denver because of altitude. Unless you cook it in a pressure pot. And that amounts to steaming it. 

Notice Chef John with Food Wishes doesn't bother with butter browned to a hazelnut color, beurre noisette, actually, a French sauce, an element that adds depth.

Meringue mushrooms.

I did this one time. Wanna see 'em? I didn't know what I was doing. But that's how I roll, just do it anyway.

You can use a fork to scratch mushroom gills into the chocolate ganache.

How else could you decorate your bûche de Noël?

Pinecones

Holly

Mistletoe

Acorns

Woodland creatures

Snowman

Autumn leaves

Candy canes

Berries

Toy hatchet

Elves

Snails

Snake

Come to think of it, mushrooms and snow don't go together, but what the heck.