Combine the lentils with 2½ cups (600ml) of the water in a small saucepan over medium heat. Cook the lentils for 13 to 15 minutes**, or until they are al dente, stirring once halfway through the cooking time. Drain the lentils and set aside.
Meanwhile, heat the oil in a large saucepan over medium heat. Add the onion, garlic, and a pinch salt and cook until the onion is translucent about 4 minutes. Add the ginger and red curry paste and stir to combine. Cook the mixture for 1 to 2 minutes, until the paste is fragrant. Add the veggies, sweet potato and mix well. (If using broccoli, you can add it in with the lentils at step 5, so it doesnt overcook)
Add the milk, remaining ¾ cup (180ml) water, salt, sugar, cayenne, lime zest, and lime juice and stir to combine. Cover and cook for 10 mins or until sweet potatoes are cooked.
Add the cooked lentils and bring the mixture to a rolling boil. Taste and adjust the seasonings. Reduce the heat to low. Add the Thai basil . Cover the saucepan and simmer for a few minutes, until the vegetables are cooked through and the flavors meld. Garnish with the basil and lime wedges.
** Split Red Lentils will take 13-14 mins to cook, whole red lentils will take 19-20 mins and brown lentils will take 30 mins to cook. Tips
Add some smooth peanut butter and curry powder for a rich and creamy Massaman-style soup.
Not a fan of lentils? Add 10 ounces (284g) cubed firm or extra-firm tofu , or cooked chickpeas instead of cooked lentils for a boost of plant-based protein.
In fall, you could use squash or pumpkin instead of sweet potatoes.
Feel free to stir in some frozen peas or some fresh spinach right in the end for some more color.