Place sugar and water in a sauce pan fitted with candy thermometer on low flame.
At the same time start whipping the chickpea brine.
Mix the sugar and water so that it melts completely.
Keep on medium low and keep watch on the temperature.
Keep on beating the brine until it reaches stiff peaks. It may take from 10 minutes to 15 minutes.
Keep flame low for the syrup if you see the temperature increasing at a high speed. We need to bring the syrup to 248°F at the same time the meringue reaches the stiff peak stage.
Now remove the syrup from flame, remove the thermometer.
While keeping the mixer running, slowly pour the syrup inside the meringue. Keep on mixing. Make sure that the hor syrup doesn't come in contact with the wall of the bowl or the beater.
Once all the syrup has gone inside, keep on beating the meringue until the bowl is cool to touch. It will take around 10 minutes to cool down. Keep on beating and the meringue will become whiter and shiny.
Touch the outside of the bowl. It should be cool.
Once cool, start adding butter by table spoons. Add a table spoon of butter and beat until incorporated before adding the next spoon.
Keep on adding until you finish with all the butter.
Now the mix will be like a curdled soup.
Keep on beating. After some time you will see that the mixture transforms to light fluffy butter cream.
Once the cream is fluffy and there is no soupy portion, you can stop beating.
Use this to frost and pipe.