1. In a large skillet, heat oil over medium heat and saute the onion, garlic, and optional bell pepper until fragrant, tender, and golden, about 8 minutes.  Add the spices and salt, and saute 1 minute.
2. Add the drained black beans, zest and lime juice to the pan. Stir well, then mash with a potato masher until mostly mashed, leaving a little texture, then stir until combined. (You could also pulse in a food processor). Taste and adjust the salt and heat level.
3. At this point you can add ¼-⅓ cup ground flaxseed if you want this vegan. Otherwise, let this cool, add the egg, optional cheese, cilantro, scallions and the bread crumbs and mix well until combined well.  Let stand 10-15 minutes in the fridge so the breadcrumbs or/flax have a chance to absorb moisture. If the mixture still feels wet, add more bread crumbs as needed.
4. Using clean damp hands, form and compress tightly into 4 large patties (or 5 or 6 smaller ones), smoothing the edges. If the mixture still seems too soft, refrigerate to firm up, for 30 minutes.
5. Heat 1 tablespoon olive oil in a skillet, over medium heat. Sear each side 5-7 minutes, or until golden and heated all the way through (you want the egg to cook though). Place in a warm oven until ready to serve – and feel free to top with melty cheese. Alternatively, you can bake these on a parchment-lined sheet tray ( spray the tops with olive oil) and bake for 20 minutes at 375 F , flipping halfway through.
6. Refrigerate the black bean burgers for up to 4 days. ( Or freeze for later)
7. To reheat, warm in an oven, toaster oven or on the grill. (Great for making ahead)

Serve on toasted buns, with chipotle mayo, Mexican slaw or Curtido and avocado if you like, or over a bed of dressed greens and/ and grains with fresh veggies!