Melt ghee in a Dutch oven over medium heat. Add onions and cook covered for 15 minutes, stirring occasionally.
Stir in coconut sugar and garlic, then cook uncovered for an additional 10 minutes or until the onions are soft.
Add sherry and coconut aminos, then continue to cook uncovered for 5 minutes.
Pour in beef stock, nutritional yeast, and pepper. Bring to a boil, then reduce heat to low. Let simmer for 20 minutes.
Preheat the oven broiler.
Ladle the onion soup into oven-safe bowls and sprinkle with shredded cheese.
Top with a slice of paleo bread and sprinkle with additional cheese.
Transfer to the oven and broil for 2 minutes, or until the cheese is melted and lightly browned.
Serve hot and enjoy!