Melt and temper the chocolate

• Melt the dark chocolate in a bowl over a bain-marie, stirring gently.
• Temper the chocolate to about 31°C using a thermometer so it sets glossy and snaps.
• Keep the tempered chocolate warm and fluid for sculpting.

Build the main body

• Pour tempered chocolate onto a sheet and let it set into thick slabs.
• Cut and assemble the slabs into the torso, chest and legs of Optimus Prime.
• Weld the pieces together with a little melted chocolate and smooth the seams with a scraper.

Sculpt the head and details

• Carve the helmet, face plate and antennae from set chocolate.
• Shape the arms, shoulders and wheels of the truck form.
• Attach every piece with melted chocolate and refine the edges.

Add colour and finish

• Melt cocoa butter and tint it red, blue and silver.
• Brush the colours onto the armour panels to match Optimus Prime.
• Let the sculpture set completely on a cooling rack before displaying.