01 - Steam or boil the diced sweet potatoes until fork-tender, about 10-12 minutes. Drain thoroughly and mash in a large bowl until smooth but with some texture remaining.
02 - Add the cooked lentils, chopped red onion, minced garlic, fresh herbs, cumin, smoked paprika, coriander, salt, black pepper, and chili flakes to the mashed sweet potatoes. Mix until evenly distributed.
03 - Stir in the flour and egg (or prepared flax egg) until the mixture holds together when pressed. Adjust consistency with additional flour if too wet, or a splash of water if too dry.
04 - Divide the mixture into 8 equal portions and form into patties about 1/2 inch thick. Press firmly to ensure they hold their shape during cooking.
05 - Heat olive oil in a large nonstick skillet over medium heat. Cook patties in batches without overcrowding, frying for 4-5 minutes per side until golden brown and crispy.
06 - Transfer cooked patties to a plate lined with paper towels to absorb excess oil. Serve warm accompanied by cucumber-yogurt sauce, spicy tomato chutney, or a fresh side salad.