Making Tartine's Chocolate Mousse Cake at Home

Making Tartine's Chocolate Mousse Cake at Home

This is how I made Tartine's famous mousse cake for my brothers' birthdays this year.

I wanted to share it with them because it's the best cake I've ever eaten in the world. Once I ate it (for the first time in San Francisco), I declared "I will never eat another cake again", and I haven't. If I did, they weren't memorable.

Tartine's bakery in San Francisco makes it with Valrhona chocolate and garnishes it with gold leaf "to let you know how rich it is." They charge US$95 for a 9-inch cake; mine's bigger, and cost me about $10 in ingredients. So I'm winning!

These are largely my own notes so I can make it again. Also, I hate most online food blogs as they're filled with unreadable waffle, so needed to write something clearer for myself and everyone else.

Enjoy!

Overview — What is this "Cake"?

Tartine's chocolate soufflé cake isn't techinically a "cake", nor even a "flourless cake". It doesn't have flour (which makes it gluten-free!) and doesn't even have almond free (so it's nut-free).

It's actually a chocolate mousse, baked into a demi-soufflé, and then coated in ganache.

If that is intimidating, maybe it should be. This isn't a beginner's pound cake. There are a few distinct skills involved in making this cake. You ahve to know how to

  • Beat eggs: Beating egg whites and yoks takes a little art. It's easy to screw it up through contamination or over-beating. If in doubt, buy three times the amount of eggs you'll need.
  • Fold a mousse. Folding isn't mixing; you have to be delicate to preserve the air in the whipped egg.. Look up a YouTube tutorial.
  • Separate eggs: A little tricky, even if you have an egg separator. No contamination of the whites is allowed.
  • Melt chocolate: People burn chocolate all the time. Drives me crazy. You have to be able to eyeball it and be gentle.

But if you feel comfortable with those then you should be able to make this pretty easily.

Ingredients/Equipment (Metric)

I'm adapting this recipe of Tartine's chocolate soufflé cake for myself, which is why I'm using metric measurements. I lived in SF but since I left I'm kissing imperial measurements goodbye.

Besides, bakers regularly use grams. If you're a baker, you have scales.

  • 170g butter (salted)
  • 550g of dark (70% cocoa) chocolate (can be cooking chocolate or some packaged one like Lindt, but definitely doesn't have to be the fanciest chocolate in the world... it's delicious with mid-range chocolate) in two parts: 400g is for the mousse, and 150g is for the ganache.
  • 7 large eggs (from packs that say "700g" for the dozen)
  • 170 g granulated sugar, divided into two parts of 85g each
  • 1/4 teaspoon salt
  • 25cm spring-form cake pan
  • 1 small 200ml tub of the highest quality pure cream you can find (the kind that you can scoop an it's like ice cream)

The quality of the chocolate is important. Don't dump Hershey's or Cadbury's into there (unless it's some fancy version). You don't have to go buy expensive couverture chocolate, but using a decent 70% chocolate will make a big difference.

The quality of the cream (for the ganache) is also very important. It's the kind that's usually US$3-5 for a tiny tub. Don't use whipped cream, nor double cream, nor thickened cream, nor "pure" cream that pours.

Look at the below picture for an example of what you can commonly get in Australia (at Coles).

Meander Valley Double Cream
Meander Valley Double Cream — A$4.50 a tub from Coles

There are better creams than this but that one was plenty good enough.

Method — The Cake (or Soufflé, whatever)

First, do basic prep of the ingredients.

  • Preheat the oven to 160 degrees C for a fan-forced oven.
  • Butter the sides and bottom of the cake pan. Line it with baking paper.
  • Break the 400g of chocolate up into chunks/blocks so it will melt a bit faster.

Now make the mousse, which will be the base of the soufflé.

  • In a saucepan over medium heat, partially melt the 170g of butter (and keep on heat).
  • When it's partially melted, stir in the 400g of broken up chocolate.
  • When smooth, remove from heat and set aside, allowing it to cool somewhat.
  • Separate the 7 egg yolks and whites, placing each into medium mixing bowls.
  • Put half the sugar (85g) into the egg yolks bowl. Beat using an egg beater/electric whisk for at high speed until it forms soft ribbons (they'll fold away after a few seconds once you stop beating). It should take 3-7 minutes.
  • Use a rubber spatula and fold the butter/chocolate mixture into the yolk bowl until loosely combined (doesn't have to be uniform).
  • Clean the whisk attachment very well or get a different one. Add the other half of the sugar (85g) into the bowl with the egg whites. Beat it until stiff peaks form. These peaks should stay — they're uncooked meringue.
Making Tartine chocolate mousse soufflé cake - egg white mixtures
Prior to folding together the chocolate and egg whites. On the left is the chocolate and beaten egg yolk , and on the right is the beaten egg whites. The zucchini will not make it into that cake!

Now fold the mixtures together using a rubber spatula.

  • Get 1/3 of the egg white mixture and gently fold that in to the chocolate mixture, to lighten it up.
  • Then fold in the remaining two thirds. Fold until there are no more white streaks visible. Make sure you scoop up the chocolate from the bottom of the bowl!
  • Pour the mixture into the springform pan.
chocolate mousse poured into a tin, ready to become cake
Tartine chocolate soufflé cake in mousse form, before it's baked
  • Bake it until the top is not shiny and before it totally puffs up: about 30-40 minutes (I stopped mine at 30).

You actually shouldn't let it puff up at all according to other instructions. Mine did a little, and it was still amazing. I think a little is fine, if not inevitable.

Cooked Tartine chocolate soufflé cake — Still a tiny bit shiny. Don't let it puff up more than this.

Let it cool completely on a wire rack, then refrigerate at least for a few hours.

The cake will initially be somewhat puffed up, but it'll collapse. This is fine!

Method — The Ganache

While the cake is cooling, make the ganache. This is the thick cream that goes on top of the cake.

  • Grate the 150g dark chocolate into a mixing bowl.
  • In a saucepan over medium-low heat, melt the tub of pure cream. Melt it until it has melted and then JUST before it's about to start boiling.
  • Pour the hot melted cream over the bowl of grated chocolate.
  • Let it sit for a couple of minutes, then stir it together. It'll become a uniform lighter chocolate coloured mixture.
  • Pour the mixture over the cake and even it out. I spread it over the sides as well.
Tartine chocolate soufflé cake with ganache poured over it
Molten ganache pourved over the cake.

The ganache will cool and solidify in the fridge.

Finishing and serving

I let the finished Tartine cake sit overnight in the fridge, but a couple of hours is probably enough. The ganache will become thick, like a dense ice cream. The cake will become fudgy and intense.

The finished chocolate Tartine mousse soufflé cake.
The finished cake. The ganache isn't hard, but definitely needs a sharp and thin knife to cut through.

Serve it with a side of cream or vanilla ice cream. If done well, people won't be able to speak while they eat it.

Why post this recipe for Tartine's Chocolate Souffle Cake?

Just a quick note — I posted this recipe mostly for my own archive, so I can do it again.

I know, Hooshmand.net this isn't a food blog. This is a blog about doing difficult things that I like. Usually, that's motorcycles (lots of them!), code, and unusual business concepts. But today, it's making a cake because it's the best goddamn cake in the world and it wasn't easy to make.

To me the essence of winning in this world is being a guy who can not only ride and fix motorcycles and lift very heavy things over my head, but can also speak a bunch of languages, cook amazing food, know multiple art forms, and be thoughtful about the world and nice to people along the way.

There may be another couple of recipes later — who knows.