Cut the head of escarole in half lengthwise, then cut each length crosswise, into 1 1/2-inch strips. Place in a large bowl and cover with cold water. Use your hands to swish the leaves around, loosening up the dirt. Let the escarole sit undisturbed for 5 or so minutes so that the soot settles to the bottom. Lift the escarole out of the bowl, then repeat the washing process. (Escarole is very dirty—washing it twice is critical.) Don’t worry if the leaves are still a little wet.
In a large Dutch oven with a lid, heat the oil over medium-high heat, Once hot, add the rosemary sprig and the chiles de arbol. Let sizzle for about 1 minute, then turn the heat to medium and add the garlic. Stir until it’s soft and golden on the edges.
Add the escarole a handful at a time. Stir it and let it wilt before adding the next handful and season with salt as you throw in each new addition.
When all the escarole has wilted, add the beans, the stock, and the cheese rind (if using), season with more salt, and stir to mix everything together.
Bring to a gentle simmer, then cover, lower the heat to maintain a slow simmer, and cook until the greens are tender and the liquid has thickened, about 20 minutes. (If you don’t want the dish to be soupy, you can remove the lid and simmer it for about 5 minutes, until the liquid has reduced.)
Before serving, season with lemon juice, salt, and pepper. Garnish with grated cheese and a swirl of olive oil. Serve over slices of toasted sourdough, polenta, or al dente ditalini.
Optional: If you’d like to add a bit of flair, garnish with a fried rosemary sprig. Heat about an inch of canola oil in a high-sided pan. When it’s shimmering (about 375° F), add the rosemary sprigs. Fry for about 30 seconds, until crisp, then use a slotted spoon to transfer to a paper towel-lined plate or baking sheet. Sprinkle with salt while warm.