Garden Royalty

So my summer harvest has begun in all earnest and I'm starting to panic about the volume of food. My latest success is the purple beans. These are Violet Queens & Purple Kings (bush & climbing).
Sadly, they turn green when cooked - I'm trying to find the fine line between cooked & warm that my children will still eat. The ToddlerTerror isn't as keen on these raw as he is the 'matoes' & 'sorberries'

Here's someone else fascinated by purple vegies and an idea to keep their colour which I'll have to try out - preserving the purple in vegies. I wonder if lemon juice would tenderise them, without cooking out the purple?
A perfect suggestion for my early glut came from My Carolina Kitchen, looking forward to trying this for NYE visitors.
And some great bean recipes.