In a large skillet or frying pan, sauté the onions and garlic together with some olive oil until just soft. Transfer to a bowl.
Add more oil to the pan (the heat should be medium-high) and then add the beans. Spread them out into a single layer.
Let the beans get crisp; cook, in a single layer, for at least 2 minutes without stirring. Stir and do the same for the other side of the beans. Cook until beans are crisp and blistered all over.
Add the onions back into the skillet with the kale and broth. Stir well.
Cook until the kale has wilted; season with salt, pepper and red pepper flakes to your liking.
Serve alone or atop rice or quinoa. Garnish with fresh tomatoes. This dish also tastes great with Parmesan, feta or goat cheese on top.