Well it's the same principle as making normal butter icing, where you would use softened butter and icing sugar (if you haven't done this before, maybe your wife has?). I'd find it really hard to give quantities because its very much a "by eye" thing, but you want to start out with some room temperature (ie not melted, but not hard - nice and squishy so you can mash it with a fork) *unsalted* butter. Then you would add some coconut flour, again the amount would depend on the amount of butter you're using, but maybe start with a couple of heaped tablespoonfuls. Then using a fork beat it really hard, mixing round and round very fast, until the coconut flour is beaten in and the butter looks quite fluffy. At this point it is customary to taste it 
. Then there's a few things you can do
You could add a little bit of sweetener, eg stevia
You could add some dark cocoa if you want a chocolatey icing
You could add a bit of rum or some brandy if you want that (don't put too much in, it will make the mixture too runny)
If it still tastes more of just butter than anything else, then you need to put more coconut flour in
(If your wife has made butter icing before, she'll be able to show you better than I can explain)
Type 2 on Metformin, diagnosed Jan 2013, ultra low carber, Hba1C at diagnosis 8% (11mmol), now between 4.5 and 5.5 mmol. 20kg lost so far
. Then there's a few things you can doYou could add a little bit of sweetener, eg stevia
You could add some dark cocoa if you want a chocolatey icing
You could add a bit of rum or some brandy if you want that (don't put too much in, it will make the mixture too runny)
If it still tastes more of just butter than anything else, then you need to put more coconut flour in
(If your wife has made butter icing before, she'll be able to show you better than I can explain)
Type 2 on Metformin, diagnosed Jan 2013, ultra low carber, Hba1C at diagnosis 8% (11mmol), now between 4.5 and 5.5 mmol. 20kg lost so far
