The 1M tip is included in the Wilton cupcake decorating kit - I think you can buy them in Target stores now. Otherwise I've seen them on eBay on their own.

Amanda

I've made these a couple of times now - they are so delicious!  I love being able to make the caramel from a tin of condensed milk in the Thermie without the worry of the can exploding like the old boiling in the saucepan method.  I cooked my condensed milk for an extra 30 mins as Tenina suggests in the notes if you want a deep caramel colour and that was perfect for the way we like it.  I topped the water up a bit after the first hour. 

The whole family loves these so they will be made again and again!

I started using the name tortagianduia about 3 years ago on various forums.  It is shortened from torta alla gianduia (aka Nutella cake!) - the first Nigella recipe I made   

Amanda