In a large bowl, combine the cooked lentils, fresh chopped spinach, breadcrumbs, and grated Parmesan cheese (if using). Add the finely chopped onion, minced garlic, ground cumin, smoked paprika, salt, and black pepper. Mix thoroughly until all ingredients are evenly distributed.

Next, crack the large egg into the mixture and stir until it's well combined. If the consistency feels too wet, gradually mix in more breadcrumbs until the mixture holds together firmly.

Divide the mixture into four equal portions, then shape each portion into a patty that’s about 1 inch thick. Press the mixture together firmly.

Heat a tablespoon of olive oil in a non-stick skillet over medium heat until it shimmers. This will help achieve a golden brown crust.

Carefully place the patties in the skillet and cook for 4-5 minutes on each side until golden brown and crisp. Cook in batches if necessary.

Once cooked, transfer the burgers to a plate lined with paper towels. Serve on buns with fresh toppings.