If anyone is interested, here is a HP Soap Frosting recipe I came across a while back. I did try it once recently and it was a lot of fun.
For Hp Soap Frosting graciously shared by Janelle Peterson
Make your soap as you normally would using hot process.
In a smaller pan add 1 ounce of stearic acid, 7 ounces of water and 2 ounces of glycerin.
Allow it to melt and mix. I was told to add 5 ounces of mp soap base to this but I did not.
You can try if you like but I do not know how it will turn out. I made mine without as I didn’t have any on hand.
While this is melting get a larger pan and measure out 12 ounces of hp soap.
When your stearic acid pan had melted, pour into the larger pan of hp soap. Mix this together on medium heat and stir until completely combined. You want this to be fluid. If it is still real thick you can add in some liquid. You have many choices. Goats milk, coconut milk, aloe gel or juice or just add more water. I like goats milk for mine. Only add small amounts until it is fluid again.
When your soap is completely melted and fluid, stir in 12 ounces of baking soda. This is also when I added my mica. Cook and stir until soap is smooth to the touch and not gritty. You do not want to stop stirring. This will not take very long. Do the finger test. As soon as it is no longer gritty remove from the heat.
Allow to cool and add your fragrance and preservative at the correct temp for your specific preservative. You will need one due to the extras you have added. Do not let this get cool. You want it fairly warm.
After you have added your fragrance and preservative you will mix with your beaters until you get nice stiff peaks but still warm. Put into your piping bag and you are set to go.
I got 20 cupcakes out of this. You will get more or less depending on how tall you make them.
Note: after 4 hours the frosting is solid but spongy…
To make a rebatch soap frosting just replace the 12 ounces of hp soap with shredded cp or hp soap. add 9 ounces of water instead of 7.