Italian meringue buttercream, coffee

Dissolve the instant coffee crystals in the vanilla extract to make a concentrated coffee flavouring.

Put the egg whites in the mixer bowl with a pinch of salt and the cream of tartar.

Put the sugar in a small saucepan and pour the water around the outside of the pot to wash down stray crystals.

Cook over medium heat, stirring until dissolved and the syrup goes from cloudy to translucent; stop stirring once it boils. Brush down the sides with water to prevent crystallisation.

At the boil the syrup is around 212F. Start whipping the egg whites now so both are ready together.

Take the syrup off the heat at 245F.

With the mixer running, pour the syrup down the side of the bowl so it trickles into the whites without hitting the whisk. Increase speed as it goes in.

Beat until the side of the bowl is room temperature.

Add room temperature butter to the room temperature meringue with the whisk, then switch to the paddle to smooth it out. It will look soupy, then curdled; keep going and the emulsion reforms.

Beat in the coffee flavouring, about two teaspoons of liquid; do not add much more than that.