Finely chop the biscuits, then add the peanut butter: you will need to obtain a workable mixture.
Separately, melt the chocolate (in the microwave or in a bain marie).
Create the heart of the chocolates by forming balls of mixture (make them small, smaller than 1 walnut) and let them rest in the freezer for 20 minutes.
Pass the balls, one at a time, in the chocolate, then place them on parchment paper: if the layer of chocolate seems uniform enough, let them rest for at least 20 minutes in the fridge, otherwise let them rest in the fridge for only 10 minutes, then dip them again in the chocolate and put them back in the fridge for at least another 10 minutes.
Decorate the truffles to taste with peanut butter (I put it in a sac-à-poche to create subtle decorations).