Rinse the red lentils thoroughly under cold water and add them to a large pot with 2.5 cups of water. Bring to a boil over medium-high heat, then reduce to a simmer. Cook for about 15 minutes until the lentils are very soft and starting to break down, then drain any excess water.
While the lentils cook, finely chop the onion and mince the garlic. In a skillet, heat 1 tablespoon of oil over medium heat and sauté the onion and garlic until fragrant and translucent, about 3 minutes.
Transfer the cooked lentils to a large mixing bowl and mash them with a fork or potato masher until mostly smooth, leaving some texture for bite.
Add the sautéed onion and garlic to the mashed lentils, then stir in the breadcrumbs, cumin, smoked paprika, and beaten egg. Mix everything thoroughly until you get a sticky, cohesive dough.
Divide the mixture into 4 to 6 equal portions and shape each into oval or round patties about an inch thick. Place the shaped cutlets on a plate or tray.
Heat 2 tablespoons of oil in a skillet over medium heat until shimmering. Carefully place the cutlets in the pan without crowding, and cook for about 4-5 minutes per side until golden brown and crispy.
Use a spatula to gently flip each cutlet, ensuring they develop a crispy exterior. Cook the other side until equally golden and crispy, about 4 more minutes.
Transfer the cooked cutlets to a plate lined with paper towels to drain excess oil. Let them rest for a couple of minutes to firm up.
Serve the lentil cutlets warm, perhaps with a squeeze of lemon or your favorite dipping sauce. Enjoy their crispy exterior and tender inside as a nostalgic, satisfying meal.
