Heat the olive oil in a large pot over medium heat. Add the onion and cook until it softens.
Stir in the garlic, ginger, and turmeric. Cook for one minute until the spices smell fragrant.
Add the lentils, butternut squash, diced tomatoes, and vegetable broth. Bring the mixture to a boil.
Reduce the heat to low, cover the pot, and simmer for 25 minutes until the lentils and squash are tender.
Stir in the kale and cook for 5 more minutes until the greens wilt.
Season with salt and pepper. Remove the pot from the heat and stir in the lemon juice before serving.