Melt half the ghee in a large skillet set over medium-high heat and then throw in the chopped onion; cook until softened, fragrant and slightly colored, about 2 minutes.
Then, crank up the heat and add the ground beef and salt. Break the meat into little pieces with a wooden spoon to help it cook faster and continue cooking until the meat is no longer pink, about 7 or 8 minutes. Throw in the ground pepper, garlic powder, fish sauce and Frank's Red Hot (if using) and stir.
Transfer the cooked meat to a bowl and return the skillet to the heat source. Melt the remaining ghee and add the sweet potatoes to the skillet. Cook until nicely caramalized on each side, about 1 minute per side.
Return the meat to the skillet, mix to combine with the sweet potatoes and then mound the spinach leaves on top. Kill the heat and cover with a large heat resistant bowl. Let sit for 5 minutes to allow the spinach to wilt.
When the spinach has wilted enough to allow stirring, mix it in very delicately, until all the ingredients are well distributed.
Serve piping hot with a few teaspoons of Harissa.
Notes
*To bake the sweet potatoes, simply wrap them in foil and bake in a 375F oven for 45 minutes to an hour (depending on size) or until they feel soft when you squeeze them lightly with your fingers. Make a few ahead of time and keep them in the refrigerator.