Drain and rinse the canned black beans well. Place beans in a large bowl and mash with a fork or potato masher until mostly broken down but still slightly chunky (about 1–2 minutes). Leave some texture for bite.

Combine ingredients

To the mashed beans add rolled oats, chopped red onion, minced garlic, chopped cilantro, ground cumin, smoked paprika, salt, black pepper, and lime juice. Mix until combined. If using egg or flax egg, add now to help bind. The mixture should hold together when pressed; if too wet add up to 2 tablespoons more oats, if too dry add 1–2 teaspoons water or a splash of lime juice.

Form patties

Divide the mixture into 4 equal portions (for 4 burgers). Using your hands, form each portion into a compact patty about 3/4-inch thick and 3.5–4 inches in diameter. Place formed patties on a plate or baking sheet and chill in the fridge for 15 minutes to firm up (optional but helps them hold together).

Cook patties

Heat a large nonstick or cast-iron skillet over medium heat and add 2 tablespoons olive oil (plus 1 tablespoon vegetable oil if you want extra crisp). When the oil shimmers, add patties (do not overcrowd). Cook 4–5 minutes per side, pressing gently once with a spatula, until a golden crust forms and patties are heated through. If using pepperjack cheese, add a slice to each patty in the last minute of cooking and cover the pan briefly so the cheese melts.

Avocado Pico

In a medium bowl combine diced avocado, diced tomato, chopped red onion, minced jalapeño, chopped cilantro, lime juice, salt and black pepper. Gently toss to combine, being careful not to mash the avocado. Taste and adjust seasoning, adding more lime or salt as desired. Keep chilled until assembly.

Sriracha Pepperjack Mayo

In a small bowl whisk together mayonnaise, sriracha, lime juice, and garlic powder until smooth. Taste and add more sriracha if you want more heat. Keep refrigerated until ready to assemble.

Assembly & Serve

Toast burger buns lightly in a dry skillet or toaster until golden.

Spread about 1 to 1 1/2 tablespoons of the sriracha mayo on the bottom bun. Place a handful of mixed greens on the mayo, then the warm black bean patty with melted pepperjack. Spoon 2–3 tablespoons of avocado pico over the patty (more if desired). Add pickled jalapeños if using, then spread a little mayo on the top bun and close the burger.

Serve immediately with your choice of sides. Leftover patties can be refrigerated for up to 3 days or frozen up to 1 month.