There is consequently a narrow harvesting window: if you miss it, you have animal feed.
They have a thin skin, nowhere near as strong as that on beans, and so fall apart when cooked.
In the UK, they mostly appear as mushy peas. In the UK and Canada, you can buy them dried, with a tablet of Sodium bicarbonate to put in the soaking water to soften them to hasten their turning to mush.
You can also buy can who Marrowfat Peas in a can, ready to heat and serve, or cook further as desired.
In Asia, Marrowfat Peas are made into snack foods, such as Wasabi Peas.
The name Marrowfat comes from the name of the maro pea variety.