Peanut caramel macarons

This is my third attempt at the classic French macaron. Notoriously difficult and I have again learnt some valuable lessons: aging your egg whites (haven't done this but will do it from now on, for at least 24 hours, so just separate your eggs the night before you bake); not too build up the macaronage too much by folding in even more air as you will end up with air bubbles and an uneven shell. I baked at a lower temperature this time but slightly longer and I had let them rest to dry out for longer (for an hour).

PEANUT MACARONS WITH SALTED CARAMEL

3 egg whites
50g light brown sugar
60g ground almonds
50g ground peanuts
200g icing sugar

for the caramel
125 brown sugar
1 vanilla pod
60g salted butter
50ml double cream

Blend the ground almonds, ground peanuts and the icing sugar and sift in a bowl . In a separate bowl beat the egg whites until they start to stiffen and slowly add the sugar. Mix some more until stiff and shiny. With a spatula fold under the nut and sugar mix but don't overwork the mixture. Place into a piping bag and pipe 3cm circles onto a baking tray lined with grease proof paper. Let rest for one hour. Preheat the oven to 150°C. Place in the oven and bake for 10-15 min, depending on size. Leave to cool.
To make the caramel dissolve the sugar and 3 tbsp water in a pan. Slit open the vanilla pod open lengthways and scrape out the seeds and add. Stir in the butter and raise the temperature until it bubbles and caramel turns toffee colour. Take off the heat and gently stir in the cream. Let cool before applying it on the macaron halves and sandwich together.