It’s just broad beans. What you said is normal for them to turn black after frying, because you fry them with the skin on, right? It doesn’t affect the food, it’s just for the senses. As for the cooking method, I just leave the skin on Fry, add some leeks; peel and scramble eggs so they don't turn black; peel and stir-fry red peppers. I like this better, hehe. Give it a try!