Heat the olive oil in a large pot over medium heat. Add the onion and cook for 6–8 minutes until soft and lightly golden.
Add the garlic, smoked paprika and thyme and cook for 1 minute until fragrant.
Add the mushrooms and cook for 5–6 minutes, allowing them to release their moisture and begin to brown.
Stir in the lentils, tomato purée and vegetable stock, then bring to a gentle simmer.
Reduce the heat and cook uncovered for 30–35 minutes, stirring occasionally, until the lentils are tender and the stew has thickened.
Season well with salt and black pepper and serve hot.
