In a large pot, heat a bit of oil over medium heat. Add the diced onion and sauté for 3–4 minutes until soft. Add the garlic and cook for 1 more minute.
Stir in the Thai red curry paste and cook for 1–2 minutes to release the flavors.
Add the red lentils, vegetable stock cube, 2 cups of water, and the can of coconut milk. Stir well to combine.
Add the diced vegetables of your choice. Bring the soup to a boil.
Reduce the heat to low and let the soup simmer for 15-20 minutes, or until the lentils are soft and the vegetables are cooked through. Stir occasionally.
Add a squeeze of lemon or lime juice to brighten the flavour. Taste and add more curry paste, salt, or pepper if needed.
Serve hot, optionally garnished with fresh herbs like cilantro.
Enjoy the meal!