Place the sweet potatoes on a baking sheet. Sprinkle with salt and ground black pepper and coat with a teaspoon of the olive oil.
Bake in a preheated 450-degree Fahrenheit oven for 40 minutes. Remove and set aside to cool.
Heat the remaining teaspoon of oil in a saucepan. Add the onions and garlic and ginger. Sprinkle some salt. Saute over medium heat until the onions turn translucent, about four to five minutes.
Add the cayenne and garam masala. Stir to coat the onions, then add the chopped kale and cook, stirring, 2-3 minutes or until the kale has wilted and is tender.
Add the coriander leaves and lemon juice, mix well, then turn off the heat. Check seasoning and add more salt if needed.
Cut each sweet potato down the middle, lengthwise. Scoop out half of the flesh with a spoon and place in a bowl. Mash the sweet potato mixture, then add the cooked kale mixture to it and mix well.
Scoop back the mashed sweet potato and kale mixture into each of the sweet potato halves.
Place the sweet potato skins back on the baking sheet and bake in a preheated 450-degree oven for 15 minutes for the skins to crisp up.
Serve hot, drizzled with some cinnamon cream. To make the cinnamon cashew cream, place all the ingredients in a blender and whiz until you have a really smooth cream.