Bolo de Bolacha / Portuguese Biscuit Cake

This is my take on the delicious, popular Portuguese biscuit cake - alternating layers of Marie biscuits soaked in strong coffee with sweet, rich buttercream.  YUM!

In Portugal, the shape of this cake is usually free form (think seven little biscuit towers forming a pretty flower shaped cake).  However, I like using a cake ring as I find it easier to assemble. You can decorate the layered cake with extra dry, crushed biscuits or flaked almonds if you like.

Enough for a 20cm round cake, serves 12

BISCUIT LAYERS

Marie biscuits (or a plain, sweet biscuit variety such as Vanilla Wine biscuits), 400g - approximately 2 packets

espresso/strong coffee, 250ml (1 cup) - cooled slightly

ESPRESSO SWISS MERINGUE BUTTERCREAM

egg whites, 3

caster sugar, 150g (180ml or 3/4 cup)

icing sugar, 165g (250ml or 1 cup)

unsalted butter, 200g - at room temperature or softened

fine salt, 1.25ml (1/4 teaspoon)

espresso/strong coffee, 15ml (1 tablespoon) - cooled

To start, make the Swiss meringue buttercream by placing the egg whites and caster sugar in a large heat proof mixing bowl (I use a stainless steel free standing mixer bowl).  Set it over a medium saucepan of simmering water (making sure the surface of the water does not touch the bowl).

Whisk by hand for a few minutes until the sugar has dissolved (you can test this by rubbing a bit of the mixture between your fingers - when ready, is should feel smooth) and the mixture feels warm to touch (about 65°C - 70°C on a thermometer if you are unsure). 

Note: You are not trying to whip the meringue at this stage but instead you just want to dissolve the sugar and cook the egg whites gently.

Remove from the heat and whisk on a high speed with electric beaters or an electric mixer until the meringue is stiff and glossy.

Add the icing sugar and beat until uniform (slow at first to prevent being engulfed by a cloud of icing sugar).

If the meringue still feels very warm, slow the mixer to a medium speed and whisk for a few minutes until the mixing bowl is cooler to touch (i.e. the meringue reaches room temperature).

Add the soft, room temperature butter and whisk on a high speed until smooth and glossy (at least 2 - 3 minutes).

Once the buttercream is smooth, add the salt and espresso and mix until uniform.

(If after several minutes of mixing the mixture seems split, the butter might be too cold - warm the mixing bowl gently using a bain-marie then whisk again on a high speed.  If the buttercream looks very runny, the butter or the meringue might be too warm - cool the mixing bowl for a few minutes in the fridge, then whisk again on high).

I've used a cake ring to assemble the cake, but you can easily do it free form (traditional).

To assemble, spread a thin layer of buttercream onto your serving plate, then place a cake ring on top of the plate (if using).

Soak one or two biscuits at a time in the cooled coffee, only for a few seconds (enough to slightly soften them but still holding their shape - it is a fine balance).  Place a few soaked biscuits on the plate.

Spread a very thin layer of buttercream over the first layer of soaked biscuits.

Repeat the layering until all the biscuits are used (or until you are happy with the cake's size).

Refrigerate the cake for an hour or two (or if you have the patience, overnight).

Remove the cake ring (if you used one - a little bit of heat on the outside of the ring with a blow torch really helps). 

If you like, you can decorate the cake with extra crushed biscuits or flaked almonds before serving.

Best enjoyed with a "bica"!