Mirror Mirror Glaze

 


This week’s bake is another Valentine’s Day celebration:  White Chocolate Mousse Cake with Mirror Glaze from Chef Anna Olson.  It’s a Chocolate Cake surrounded by White Chocolate Mousse, with a Raspberry jelly filling and topped with a pink and white Mirror Glaze.


“Whatever may be their use in civilized societies, mirrors are essential to all violent and heroic action.“

Virginia Woolf

Mirror glaze is the impressive and seemingly effortless technique used to decorate mousse cakes, entremets, and pastries. Though it’s recently experienced a resurgence in popularity, mirror glaze is actually deeply rooted in classic French haute pastry.

The classic French technique, named glacage mirroir (mirror glaze) for its impossibly perfect gloss, is common in entremets, a stalwart from the haute patisserie canon. The glaze encases the intricate layers, keeping it fresh and adding oh la la.

Like any technique, it’s not just about looks. A defining glaze is flavourful, but not too sweet (often from a combination of caster sugar, white chocolate and sweetened condensed milk), and is thick, but supple, almost delicate (usually from gelatine, as well as glucose or pectin).

Mirror glaze gets its unique reflective quality from the addition of bloomed powdered or sheet gelatin. In order for a mirror glaze to work its magic and properly harden, it must be poured while warm (around 90°F) onto a smooth, cold or room temperature surface. That means that all components of a mirror cake are usually prepared and cooled ahead of time.

Here is the recipe:

Ingredients

Chocolate Cake Layer:

1 cup (200 g) granulated sugar

¾ cup (110 g) all-purpose flour

½ cup (60 g) Dutch process cocoa powder

1 tsp baking soda

½ tsp baking powder

½ tsp fine salt

½ cup (125 mL)buttermilk

½ cup (125 mL) warm coffee

¼ cup (60 mL) vegetable oil

1 large egg

1 tsp vanilla extract

Raspberry Jelly:

6 oz (180 g) frozen raspberries, thawed

2/3 cup (140 g) granulated sugar

3 Tbsp (54 g) honey

1½ tsp gelatin powder

3 Tbsp (45 mL) cold water

White Chocolate Mousse:

10 oz (300 g) chopped white couverture/baking chocolate

¼ cup (60 mL) cold water

1 Tbsp (7 g) unflavoured gelatin powder

2 cups (500 mL) whipping cream, divided

White Chocolate Mirror Glaze:

2 Tbsp + 1 tsp (18 g) gelatin powder

1 cup (250 mL) cold water (divided)

12 oz (360 g) white couverture/baking chocolate, chopped

¾ cup (150 g) granulated sugar

2/3 cup (160 mL) sweetened condensed milk

Food colouring gel or paste, including white

8-inch (20 cm) cardboard cake board


Method

Preheat the oven to 350°F (180°C). 

Grease two 8-inch (20 cm) round cake pans. 

Line the bottom of the pans with parchment paper and dust the sides of the pans with flour, knocking out any excess.

Sift the sugar, flour, cocoa powder, baking soda, baking powder and salt into a large bowl. 

Add the buttermilk, coffee, oil, eggs and vanilla to the bowl and whisk vigorously by hand for about a minute, until smooth. 

Pour the batter into the pans and bake for 30 to 35 minutes, until a tester inserted into the centre of the cake comes out clean.

Cool the cakes in their pans on a cooling rack for 30 minutes before turning out to cool completely before frosting. 

The cake layers can be made a day ahead, wrapped individually and left on the counter before assembling, or they can be frozen for up to 3 months before thawing on the counter.

For the raspberry jelly, line a small, shallow bowl no wider than 8 inches/20 cm across with plastic wrap. 

Lightly grease the wrap.

Purée the raspberries and then strain them through a fine-mesh sieve, discarding the seeds. Measure ½ cup (125 mL) purée into a small pot. 

Add the sugar and honey and bring to a simmer over medium heat, stirring occasionally, until the sugar has fully dissolved.

While the raspberry mixture heats, sprinkle the gelatin powder over the cold water in a small dish and let sit for 2 minutes until bloomed (the gelatin absorbs some of the water and plumps up). Remove the raspberry mixture from the heat and stir in the gelatin until dissolved.

Pour the jelly into the prepared dish, cool to room temperature and then freeze until set, about 90 minutes. This jelly can be prepared days in advance and frozen until ready to assemble.

For the mousse, lightly grease and line the bottom and sides of a 9-inch (23 cm) springform pan with parchment paper (if you have acetate, line the sides of the pan with acetate, for a smooth finish). 

Have the white chocolate ready in the bowl of a food processor or a blender.

Place the cold water in a small dish and sprinkle the gelatin on top, stirring and letting it sit a minute. 

Heat ¾ cup (175 mL) of the cream over medium heat until it just begins to simmer. 

Remove the pan from the heat and stir in the gelatin until it dissolves.

Pour the hot cream over the white chocolate and blend until smooth, about 30 seconds. 

Transfer the white chocolate cream to a bowl to cool almost to room temperature, about 30 minutes. (If it sets up, then reheat to soften it again to ensure you will have a smooth mousse.)

Whip the remaining 1 ¼ cups (310 mL) of cream using electric beaters or a stand mixer fitted with the whip attachment on high speed until it holds a soft peak when the beaters are lifted.

Fold half of the whipped cream into the white chocolate mixture using a whisk (don’t worry if it deflates a little) and then fold in the remaining cream, using a spatula towards the end. 

The mousse will be pourable.

To assemble, pour half of the mousse into the prepared pan. 

Unwrap the jelly and nestle it into the centre of the mousse, flat-side up, taking care not to push it to the bottom of the pan. 

Pour the remaining mousse over this. 

Nestle in one cake layer, bottom-side up, so that it is level with the top of the mousse. 

Place an 8-inch/20 cm cake board on top of this, and press gently. Cover the cake and freeze overnight.

For the mirror glaze, sprinkle the gelatin powder over 1/3 cup (80 mL) cold water and set aside for 2 minutes to bloom. 

Place the chopped white chocolate into a larger pitcher or carafe that fits the wand of an immersion blender. 

Spoon the softened gelatin on top of the chocolate.

Place the sugar, condensed milk and the remaining 2/3 cup (160 mL) water in a medium saucepan and bring to a full boil over high heat (the mixture will bubble up). 

Boil for 1 minute while stirring and then pour over the gelatin and chocolate. 

Let this mixture sit for a minute, then use an immersion blender at low speed to combine the mixture.

Slowly pour the glaze through a fine-mesh sieve to strain out any air bubbles. 

Add a few drops of white food colouring and gently stir with a spoon. 

Divide the glaze into as many pitchers as you would like to colour. 

Add a few drops of food colouring to each pitcher and stir gently with a spoon. 

Let the glazes sit, stirring occasionally, until they cool to between 80°F and 86°F (27°C and 30°C). They will thicken as they cool, but still be fluid.

When your glazes get close to the right temperature, set up your glazing area. 

Line a baking tray with parchment paper and place a cooling rack over the top. 

Place a large ramekin or other dish with a flat surface on the cooling rack to rest the cake on.

To unmold the frozen cake, remove the outer ring and peel away the parchment paper. Place the cake board on top of the cake and invert, resting the cake on the ramekin on the cooling rack. 

If the pan does not come away easily, use a hair dryer on a low setting to warm the bottom of the pan to loosen it from the mousse. 

Gently slipping a palette knife in between the pan and mousse will loosen it so you can slide it off.

To glaze the cake, you have a few options but you want to pour relatively quickly. 

Start in the centre and then widen your pour to ensure the cake is completely covered, or start at one side and pour in a back-and-forth motion to create stripes. 

To style your cake glaze, you also have a few options:

Slowly pour the coloured glazes into one large pitcher (do not stir) and pour over the cake to create flowing stripes of colour.

Pour on a base coat of colour and then pour on stripes of different colours and use a palette knife to blend them like a watercolour.

Keep it simple and pour one colour onto the cake. 

You can add splatters of pearl dust mixed with a little vodka by flicking a paintbrush over the cake, or decorate simply with fresh fruit after the glaze sets.

Once pouring is complete, let the cake sit for 15 minutes to set. 

Any drips that hang off the cake can be trimmed with scissors or a knife before you carefully transfer the cake to a cake stand or platter to chill until ready to serve. 

It’s best to glaze the cake about 4 hours before serving, to allow the cake to thaw in the fridge.

Here are some pictures from the bake:





Have a great Day !


 

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