In a large bowl, beat together the eggs and heavy cream.
In 10” cast iron pan heat olive oil on medium heat. Saute the onions until translucent. Add in garlic, sweet potatoes and harissa paste. Stir making sure the harissa paste in mixed in thoroughly. Add vegetable broth. Cover pan and simmer until sweet potatoes are soft.
Stir in chopped kale and egg mixture. Cook on low heat about 3 min until bottom is set.
Add crumbled goat cheese to top of egg mixture and transfer to oven.
Cook for about 20 min until frittata is set. You can put under broiler for a couple of minutes to brown the cheese if desired.