Step 1: Build the Aromatic Base
In a large pot or Dutch oven, heat the coconut oil over medium heat. Once the oil is shimmering, add the chopped yellow onion and a pinch of salt. Sauté for 5-7 minutes, stirring occasionally, until the onion has softened and become translucent. Add the minced garlic and grated ginger, and cook for another 1-2 minutes until fragrant. Be careful not to let the garlic burn, as it can become bitter. This initial step is crucial for developing the deep, savory foundation of the curry.

Step 2: Bloom the Spices
Add the ground cumin, ground coriander, ground turmeric, and smoked paprika (or cayenne) to the pot. Stir constantly for about 1 minute. The spices will become incredibly fragrant. This process, known as “blooming,” toasts the spices in the hot oil, which unlocks their essential oils and intensifies their flavor far more than just adding them to liquid later.

Step 3: Combine the Main Ingredients
Stir in the tomato paste and cook for one more minute, allowing it to caramelize slightly. This adds a rich umami depth. Now, add the cubed sweet potatoes, the rinsed red lentils, the can of full-fat coconut milk, and the vegetable broth to the pot. Stir everything together until well combined.

Step 4: Simmer to Perfection
Bring the mixture to a boil, then reduce the heat to low, cover the pot, and let it simmer gently. Cook for 20-25 minutes, or until the red lentils have completely softened and started to break down, and the sweet potatoes are fork-tender. Stir the curry every 5-7 minutes to prevent the lentils from sticking to the bottom of the pot. The curry should have thickened considerably.

Step 5: Final Touches and Flavor Adjustments
Once the lentils and sweet potatoes are cooked, turn off the heat. If you are using greens, stir in the fresh spinach or kale. The residual heat from the curry will be enough to wilt them perfectly in just a couple of minutes. Squeeze in the juice of one lime—this is a critical step that brightens all the flavors and cuts through the richness of the coconut milk. If you feel the curry needs it, stir in the optional maple syrup or coconut sugar to balance the acidity and enhance the natural sweetness of the potatoes.

Step 6: Season and Serve
Taste the curry and season generously with salt and freshly ground black pepper until the flavors pop. Ladle the hot curry into bowls, garnish with a generous handful of fresh cilantro, and serve immediately.