Chocolate Petit Gateau

This chocolate petit gateau is a delicious dessert made up of a cake/biscuit, a decadent mousse filling and a perfect mirror glaze. You might not know anything about petit gateau, but once you do, you will want to shove them in your face every opportunity you get.

Petit Gateau: What is it?

A Petit gateau is a French dessert that consists of a mousse, a biscuit layer that can range from a cookie to a cake, or something in between, and a mirror glaze. Petit gateau can be translated to mean little cake in french. Anything that consists of a gourmet little cake is technically a petit gateau.

If your into gourmet desserts, you have probably heard of a petit gateau, and if not, we are gonna talk about it.

Petit gateau is actually simple to make. And this chocolate petit gateau can be made in less than an hour of hands on work. The trickiest part is using a silicone mold. Using a silicone mould gives the petit gateau the perfect shape. So, when you make them make sure to have a silicone mould on hand.

You may have seen some videos on instagram of people glazing desserts. 99.999% of those desserts that they are glazing are petit gateaus.

The Chocolate Mousse

Do not be intimidated. Mousse is actually easier than most people let on.

This mousse starts with a Julia Child recipe that I didn’t read correctly. Who knew that the 2 cups of whipped cream were a garnish? I have to admit that I definitely folded all of that goodness into my mousse. Then I thought, this mousse is not chocolatey enough. (Is chocolatey a word??) So I added some unsweetened cocoa powder and a little bit of vanilla. I am very proud of myself for stopping here and not adding anything else.

The cake base is super important for making a good petit gateau because it keeps the mousse sealed from the bottom. When you pour the mirror glaze over the frozen mousse, it can cause the mousse to become a little liquidy on the bottom. So placing a circle of this cake biscuit makes it a lot easier to transport the gateau’s and keep them from melting.

The Mirror Glaze:

Chocolate mirror glaze is one of the easiest gourmet elements that you can possibly make. It is only a few ingredients, unsweetened cocoa powder, gelatin, sugar, cream, and water. There you have it.

One thing nobody told me about mirror glaze that is SUPER important is that it needs to be around 90˚ degrees Fahrenheit when you pour it onto anything. (Think around toddler’s bath water temperature.) It does not have to be exactly ninety degrees but it needs to be close. If it is any hotter it will slide off the petit gateau, cake, etc. and you will be able to see through it. If it is much colder than it will be sludgy and not pour onto your petit gateau’s smoothly.

When you make this recipe don’t forget to tag me on Instagram @rosegoldandvanilla or Tag my Facebook page Rose Gold and Vanilla. Also don’t forget to save this recipe to Pinterest so that you can find it again later!

Print Recipe

Chocolate Petit Gateau

These chocolate petit gateau's are a great way to impress your friends. Filled with a light chocolate mousse, topped with a chocolate mirror glaze and set on a cake biscuit base makes this dessert a showstopper.

Course: Dessert

Cuisine: French

Keyword: Chocolate, Mousse, Petit Gateau

Servings: 6

Author: Grace

Equipment

• 3 Inch Silicone Moulds

Ingredients

Cake Base

• 1/2 cup Butter (softened to room temperature)
• 1/2 cup Sugar (104g)
• 1 Egg
• 1 tsp Pure Vanilla Extract
• 1/2 tsp Baking Powder
• 1 cup All Purpose Flour (130g)

Chocolate Mousse Filling

• 2 Egg Yolks
• 1/2 cup Sugar
• 1 tsp Pure Vanilla Extract
• 6 tbsp Butter (softened to room temperature)
• 3/4 cup Chocolate Chips
• 3/4 cup Unsweetened Cocoa Powder
• 1/8 tsp Salt
• 2 Egg Whites
• 1 cup Heavy Whipping Cream

Chocolate Mirror Glaze

• 2 ½ tsp Gelatin Powder
• 1/3 cup Corn Syrup
• 1/2 cup Water
• 1/2 cup Heavy Whipping Cream
• 1/2 cup Unsweetened Cocoa Powder

Instructions

Chocolate Mousse:

• Whisk together the egg yolks and the sugar in a heat proof bowl. Place one inch of water in a small saucepan and bring it to a simmer over medium heat. Place the the egg mixture over the water and whisk until the egg mixture is thick and is 160° degrees. Remove the egg mixture from heat. Keep Whisking until it cools slightly.
• Beat the vanilla extract and the butter into the egg mixture.
• Melt the chocolate until smooth. Let it cool slightly. Fold it into the egg mixture.
• Sift the unsweetened cocoa powder into the egg mixture. Add the salt.
• In a clean and dry glass or metal bowl beat the egg whites until they reach stiff peaks. Lightly fold them into the mousse.
• Whip the cream until stiff peaks form. Fold the whipped cream in two additions into the mousse.
• Pipe or spoon the mousse into the three inch moulds. Freeze the mousse for at least 6 hours or until firm.

Cake Base:

• Preheat the oven to 350° degrees. Line a 9×9 pan with parchment paper and spray with cooking spray.
• In a medium sized bowl cream the butter and sugar. Add the vanilla extract and the egg. Stir until combined.
• Stir in the flour and the baking powder until just combined. Spread the batter into the prepared pan.
• Bake for 15-20 minutes or until a toothpick inserted into the middle comes out clean. Let the cake cool to room temperature.
• Remove the cake from the pan. Cut out six three inch circles from the cake base.

Chocolate Mirror Glaze

• Combine the gelatin with 2 tbsps of room temperature water.
• In a small saucepan combine the water, corn syrup, cream, and cocoa powder. Let the mixture come to a simmer, stirring consistently.
• Place the gelatin in the hot glaze. Whisking until the gelatin is completely melted into the glaze. Pour the glaze through a fine mesh strainer to remove any chunks of cocoa powder from the glaze.
• Let the glaze cool to about 90° degrees, stirring occasionally so that a skin doesn't form.
• Remove the mousse from the freeze and from the mould. Place the mousses on a cooling rack with a jelly roll pan underneath.
• Pour the glaze over the top of the mousses. Covering the top completely.
• Let the glaze set on the mousses for 5 minutes. Remove the mousses from the cooling rack with a offset spatula. Place the mousses on the cake bases.
• Let the petit gateau set in the refrigerator for at least 30 minutes.
• The petit gateau's will keep in the refrigerator in an airtight container for up to 2 days.

Notes

1. The chocolate mousse is adapted from Julia Child’s Chocolate Mousse from Mastering the Art of French Cooking.
2. The chocolate mirror glaze is adapted from CBC’s Chocolate Mirror Glaze