I keep being asked how to prepare these particular beans.
Here are the culprits - picked and ready to go. You usually pick these beans when they are quite large and notice how they are flatter than your average green bean.
They tend to have stringy sides which need to be cut off. So start the first cut as in the picture below
Then continue the cut down one side of the bean as below
When you get to the bottom of that side of the bean, turn and then cut down the other side.
Now the stringy sides are gone, you have to cut little diagonal slices like below.
Now steam or boil for as long as you would normally cook pole beans and enjoy their superior taste.