Boiled gingerbread cookie dough

Last night I participated once again in our family tradition of making gingerbread cookie dough with a boiling method. You melt the fats, sugars and spices together, then add just under half of the flour while the mixture is still hot to blanch it. Then you let the mixture cool and knead in the rest of the flour by hand. Hard work!
The only similar recipe I have been able to find online is one by Martha Stewart using the trusty KichenAid.
I have two questions:
1) I know so few people who know this technique. What are other people's experiences with this kind of dough?
2) Does anyone know a tried and true way to banish flour lumps that can form when the flour is added to the hot thick liquid. I know that beating the heck out of it is the main technique, but what about sifting or quantities of each addition or some other trick?
I am hoping that during the dough curing period (put it in the fridge in a plastic bag yesterday, will let the flavours meld for a couple weeks) some of the lumps will be reabsorbed. Hoped my Mom would give me some tricks, but at 86 and doing it just once a year, she can't remember everything.