Measure the turmeric, cumin, cinnamon, and cardamom and put into a small bowl or plate.
In a large pot, add the oil, onion, and garlic. Add a pinch of salt, stir, and sauté over medium heat for 4 to 5 minutes until the onion softens.
Add spices and stir. Continue cooking for about 1 minute, until the spices are fragrant.
Add the tomatoes, coconut milk, red lentils, broth, salt, and pepper. Add red pepper flakes or cayenne, if desired, to taste. Stir to combine. Increase heat to high and bring to a low boil.
Once it boils, reduce the heat to medium and simmer, uncovered, for about 20 to 25 minutes, until the lentils are soft and tender.
Stir in the kale and cook until wilted 1 minute. Turn off the heat.
Add the lime juice.
Taste and add more salt and pepper, if desired.
Ladle into bowls and serve with lime wedges, coarse sea salt and chopped cilantro.