Preheat your oven to 180°C (350°F). Lightly grease a 9x5 inch loaf pan and set aside.
In a large skillet, heat a tablespoon of oil over medium heat. Add the finely chopped onion and minced garlic, sautéing until translucent and fragrant—about 5 minutes. The onions should become soft and slightly golden.
While the aromatics cool slightly, cook the lentils in the vegetable broth until tender but still holding shape, about 20 minutes. Drain any excess liquid and mash the lentils lightly with a fork or potato masher to create a hearty, slightly chunky texture.
In a small bowl, combine ground flaxseed with water and let sit for 5 minutes to thicken into a 'flax egg'.
In a mixing bowl, combine the mashed lentils, sautéed onions and garlic, toasted oats, tomato paste, smoked paprika, soy sauce, and the prepared flax egg. Mix thoroughly until all ingredients are well incorporated and the mixture feels cohesive but still slightly moist.
Transfer the mixture into your prepared loaf pan. Press it down firmly with a spatula or your hands to ensure it compacts evenly and holds together well.
Bake in the preheated oven for 45-50 minutes, until the top is firm, slightly cracked, and smells savory and smoky. The loaf should be pulling away slightly from the edges of the pan.
Remove the loaf from the oven and let it rest in the pan for about 10 minutes. This helps it set and makes slicing easier.
Carefully transfer the loaf onto a wire rack or serving plate. Slice with a serrated knife, revealing a hearty, moist interior with a slightly crispy crust.
Serve slices warm with your favorite vegan gravy or sauce, and enjoy the comforting, savory flavors of this plant-based classic.
