August is a bittersweet month for me. Store shelves begin to thin out with a more limited selection of fresh fruit, and I especially see less of the beautiful berries we enjoyed all summer. I had a stash of raspberries saved up and wanted to use them to make a mousse cake with something called a miroir on top. This is probably something you have seen in very high end pastries, and the term is French for mirror or reflection, because it is so shiny.
To make this, I pick up some inexpensive apple jelly at the store, add a few tablespoons of fruit puree to it, a little bit of gelatin and then heat it up in the microwave until it’s all melted, but not hot. Once your mousse cake has chilled, heat the metal rim around the cake and lift it slightly to create some space on top of the dessert to pour on the miroir. Work quickly by pouring the warm liquid on top of the cake, as it begins to set quickly, then place the cake in the refrigerator. I like using the apple jelly because it is similar to an unflavored clear gel that is available to professional chefs and used as a base for these types of applications. If you are a home baker and want to use this for some of your mousse cakes, remember that you will not get the same shine if you use only gelatin. Adding some apple jelly will give you something shinier, and closer to what you get in a pastry shop.
I find that people love to eat mousse cakes, but they very rarely try their hand at making them. Most home bakers have made chocolate mousse, but when it comes to making a fruit mousse, they usually just stick to eating the fruit.
On the commercial side, professional pastry chefs use gelatin sheets, and if you’ve never used them or even seen them before, they are exactly that- sheets of gelatin that come in three different strengths, namely gold, silver and bronze. For home bakers, the most common gelatin available is the granulated kind that you find under the Knox brand label, but this great little dessert can be made using that too. I converted my recipe so that you could make it with the granulated gelatin and it works beautifully in a pie, as a molded mousse cake and even as a filling. If you simply want to make it the mousse and pour into some beautiful stemmed glassware, along with some beautiful berries on top, it would be perfect for that too. Don’t you just love it when you have a great recipe that is not only delicious but versatile too?
I had some leftover cake trimmings which I dried in the oven and ground up in the food processor. I added a little melted butter and used them as the crust for this, but if you prefer, you can use cake as a base or use your favorite cookie wafers for the crust. You can use either Hydrox or Oreo cookies the same way – grind them up in the food processor and add a little butter to glue everything together. When making the crust, remember to remove the cream center. While you’re at it, you can add a few broken Oreo pieces to the mousse too , and this time you can leave the cream if you like.
Raspberry Mousse Cake
1 cup raspberry puree, seedless
¼ cup granulated sugar
4 teaspoons Knox gelatin (granulated)
2 ¼ cups heavy cream
½ cup to ¾ cup powdered sugar (added to cream)
Crust
2 cups chocolate cookie crumbs (can be up to 2 ½ cups if you prefer it thicker)
1 stick melted butter
First prepare the crust by putting the cookie crumbs into a bowl and adding the melted butter. Pour the crumbs out into a mold placed on some parchment on a half sheet pan. The one I used was 9.5” and is used for European style pies/tarts and even to mold mousse cakes. I used a wooden lid to flatten the crust out and then I bake it at 350°F for about 10 minutes. I let this cool completely and then make the mousse.
Next, whip the heavy cream and the powdered sugar together. I left a range for the required amount of powdered sugar because it will depend on how sweet your fruit. The raspberries I had were not that sweet, so I used almost ¾ cup.
Then puree enough fruit to make I cup of pureed fruit. I used about 3 cups of whole raspberries to get 1 cup of puree and then I passed it through a sieve to get rid of all of the seeds. When making a fruit mousses using raspberries or blackberries, make sure to do this because not everyone likes the seeds. Put the puree, granulated sugar and gelatin in a small pot and heat gently on low heat, until all of the gelatin has melted.
Mixture will be very warm but should not boil. Add to the whipped cream and whisk until mixed together and until no cream is visible, then pour this into your baked crust. Level off the top if you can, or just pour in the mousse and allow it to settle in the crust. If it does not reach the very top of the mold don’t worry about it. This will give you room to pour on the miroir once the mousse has chilled. If the mousse does reach the top, then you will have to heat the rim slightly with a torch and lift it slightly to create some space to pour on the miroir. Once chilled, prepare the miroir below and pour it on the mousse. Allow the miroir to chill completely before serving. Use a torch to warm the sides to help remove the mold. Use a warm knife to slice by dipping in a container with hot water and wiping dry before each slice.
Raspberry Miroir (enough for a 9.5-10” cake)
4 tablespoons fruit puree (I used raspberry)
1 cup apple jelly
½ teaspoon sugar
1 teaspoon Knox gelatin
Add all of the ingredients into a small pot and heat gently until everything has melted. To ensure that the apple jelly does not have any lumps, pass this through a sieve into a pourable container. Pour the warm (not hot) liquid onto a chilled or frozen mousse cake, and place in the fridge to chill completely before slicing.
Leave a Reply