I've been playing with melt & pour soap for an upcoming youth craft group, and I wanted to make some soap cupcakes, but all the recipes for icing I see are either cold process soap, which I don't make, or foaming bath butter, which is prohibitively costly for my group. So I thought I'd make a syndet bar and use that as icing.
(The soapy part of the cupcake isn't the cutest thing in the world as I was using soap left over from other projects, and I should have coloured the icing...but oh, well. I'll make some more tomorrow! The yellow ones are Lemon Curd and it combines wonderfully with Cream Cheese Icing. The pink one is Pink Sugar - again, lovely with Cream Cheese Icing fragrance!) BASIC ICING FOR SOAP CUPCAKES (feel free to double or triple - do not quadruple)
28 grams SCI noodles or flakes
26 grams Amphosol CG (coco betaine)
34 grams SLSa
3 grams cetyl alcohol
2 grams fragrance oil (I used Cream Cheese Frosting from Brambleberry. Yum!!!)
Colouring (if desired)
Heat the SCI and coco betaine in a double boiler until the SCI has melted. Add the SLSa and cetyl alcohol and again heat until all ingredients are melted. Mix well with a hand mixer, then put into a piping bag with a cake decorating tip on the end (I used a 1M). Decorate cupcakes. Rejoice.
The reason I say not to quadruple the recipe is that it does set very quickly and you will find it difficult to pipe after about 20 minutes or so. If you want to decorate a ton of cupcakes, you will want to remake the recipe again.
You can use another liquid surfactant, but SCI melts best in an amphoteric surfactant like coco betaine, so this is why I suggest it. I used cetyl because it will harden and will offer some moisturizing - you can substitute stearic acid for a harder and slightly less moisturizing icing. Feel free to add some oils - say up to 3% - to this mixture for more moisturizing!
If you aren't into melt & pour soap, you could use this icing to make some decorations for your bath bomb cupcakes (although it's not going to melt quickly in the tub)!