Kids enjoy the process (and the outcome).
Step 1: Inscribe Loving Message
Step 2: Make Moulds
First, work out how much silicone you'll need. You'll need enough to almost cover your lego pieces. This takes trial and error, if you do it the way I did. A better way is to measure the volume of your vessel including the lego - I guess you could use water and then measure how much it took. Add a few extra mls for what you won't be able to scrape out of the silicone mixing container.
Measure your silicone - you have to get this right. Use a syringe or accurate measure. Pinkysil is a 1:1 mix, and you have to get it exact or your silicone doesn't cure properly. So if your final volume is 25 ml, you need 13ml of each part (leaving only 1ml spare - so mix 15ml of each instead). Mix thoroughly and pour it in, then insert the lego.
Step 3: Complete the Mould
If you have bubbles in the silicone, blow on them with hot breath - it will pull the bubbles out. Don't use a hairdryer - too powerful.
Step 4: Extract the Mould
You can see that by the third time, I got it pretty nice. The middle image is fine and useable, the last image here is the first mould I made and I didn't mix it properly, hence the discoloured and poorly formed mould. It still works, but the lego chocolate pieces are not nice and sharp edged...
Step 5: Make Chocolate or Toffee Lego Pieces. Watch As Kids Go All Smiley. Share With Friends.
If you want a more airy candy, remove from the heat and stir in a pinch of bicarbonate soda. It will bubble up, and as it is doing so, pour the toffee our into the moulds. It will spill over the edges, but you can break that off later. More airy means less perfectly formed toffees, but lighter. No bicarb and they are more solid.
Either way, It cools pretty quickly - bend out the pieces and break off the rough edges. All done. The better your mould the better the shape. As my moulds improved, the bricks became more perfect.
** do use the vinegar in making the toffee - it helps the sugar melt properly and you can't taste it in the end.
There are tons of good toffee recipes - I guess you could make soft caramel bricks too...
** do be careful of hot toffee. It sticks to fingers and lips and burns like this: OWWWWWWW!