Preheat oven to 160°C. Line a large slice tray with baking paper.
To make the shortbread layer, place butter into the Thermomix bowl. Chop 6 sec/speed 5 or until softened. Insert Butterfly and whip 1 min/Butterfly/speed 3. Add sugars and continue whipping 1 min/Butterfly/speed 3.
Add vanilla and salt. Combine 10 sec/Butterfly/speed 3. Remove Butterfly. Add flour, peanuts and peanut butter. Blend 20 sec/speed 5.
Tip dough out into the tray. Using floured hands, press dough evenly throughout the tray. Prick surface all over with a fork. Freeze until firm for at least 20 minutes.
Bake for 30 minutes, or until brown all over. Cool.
Make honeycomb as per Thermomix instructions. Pour over the shortbread, quickly. Tilt the pan around so the honeycomb reaches the edge. Don't be tempted to spread with a spatula, it'll knock the air out. Cool.
Spread with melted chocolate. It is remarkably hard to cut this neatly on day one or even day three. It is better to leave it (at room temperature) for a few days before cutting it into shards. It is completely more-ish and very difficult to resist however.