In a large mixing bowl, combine cooked lentils, chopped spinach, breadcrumbs, Parmesan cheese, chopped onion, minced garlic, ground cumin, smoked paprika, salt, and black pepper. Mix until well combined.

Crack the egg into the mixture and stir until fully integrated. If too wet, gradually add breadcrumbs until it holds together.

Divide the mixture into four equal portions and shape into patties about 1 inch thick.

Heat olive oil in a skillet over medium heat. Test readiness by placing a small piece of the mixture in the pan; it should sizzle.

Gently add the patties into the skillet and cook for 4 to 5 minutes on one side until golden brown. Flip and cook for another 4 to 5 minutes until crisp.

Transfer cooked burgers to a plate lined with paper towels. Serve on buns with your favorite toppings like lettuce, tomato, or avocado.