Using the saute function, warm 3 tablespoons olive oil on high in an Instant Pot. When it’s hot, stir in the onion and a pinch of kosher salt, cooking until soft (about 5 minutes). Stir in the garlic, tomato paste, cumin, salt, turmeric, pepper and chile powder, and cook, stirring frequently, until fragrant (about 2 minutes).
Add the stock, tomatoes, lentils and 1 tablespoon olive oil to the pot. Cover and cook on high pressure for 6 minutes. Allow the pressure to release naturally for up to 10 minutes. If it doesn’t release by then, release the remaining pressure manually. Stir in lemon juice, then season to taste with additional salt and pepper.
To serve, divide soup between 2 bowls (for a main course) or 4 bowls (for a starter), then top each with a dollop of Greek yogurt, a scattering of mint leaves and a sprinkling of sea salt. Serve warm flatbread on the side for dipping.