(Types of sugar and measurements are English/British imperial)

I've had to change the name of this as someone else got in first - so this is the all-singing, all-dancing:

MOCHA MERENGUE

Whip 3 egg whites until just stiff.
Add 1 oz caster sugar, and whip again until stiff.
Mix 1 oz ground almonds with 3 oz caster sugar and fold into the egg whites.

Spread the meringue on non-stick baking paper in three rectangles or three circles, of equal size and not too close together (it spreads a bit).

Cook in a low oven until they are light brown and lift off the paper easily.

Meanwhile:

Put 4 oz icing sugar and 3 egg yolks in a bowl over a pan of boiling water.
Keep stirring until the mixture is thick and smooth.

Remove from the heat and keep stirring until it has cooled to blood heat (this is quicker if you put the bowl in a container of ice).

In another bowl, cream 4 oz unsalted butter until soft.
Check that the egg yolk mixture is cool enough not to melt the butter, then add it a little at a time along with a tablespoon of very strong black coffee.
Stir in 1 oz softened dark chocolate.

Make a double-decker sandwich with the meringues and mocha filling.
Wrap in foil and refrigerate.

It can then be kept in an airtight container, and will keep for quite a while (if you can manage to only eat it a bit at a time).