01 - Heat olive oil in a large pot over medium heat. Add diced onion, sliced carrots, sliced celery, and minced garlic. Sauté until vegetables are softened, approximately 5 minutes.
02 - Add rinsed lentils, diced tomatoes with their juice, vegetable broth, bay leaf, dried thyme, smoked paprika, salt, and pepper. Bring to a boil, then reduce heat, cover, and simmer for 25–30 minutes until lentils are tender. Remove and discard the bay leaf.
03 - In a mixing bowl, whisk together flour, baking powder, and salt. Cut in cold diced butter using your fingertips until the mixture resembles coarse crumbs. Stir in milk until just combined; avoid overmixing.
04 - Increase heat to bring the stew to a lively simmer. Drop spoonfuls of dumpling dough (about 1 tbsp each) onto the surface of the stew, yielding 8–10 dumplings. Cover the pot tightly and cook for 15 minutes without lifting the lid, until dumplings are puffed and cooked through.
05 - Taste the stew and adjust seasoning as needed. Sprinkle with fresh chopped parsley before serving, if desired.