- Add butter into skillet and melt on medium heat. 
- Slowly add in onions, separating them into single slices. 
- Add wine or cider and let reduce on low, without stirring. 
- Add salt and stir. 
- When onions have reduced in size by half and begin to slightly brown, add spices and stir. 
- Let reduce further, until dark brown (not burned). 
- When onions are deep brown (about 1 hour later), add in stock. 
- Let cook on low for another 30 minutes- do not let boil. 
- Preheat oven to broil on high. 
- Place the slices of bread on a baking sheet and spread a little oil on them. Bake about 1 minute till just dried out. Set aside.  
- Scoop soup into ramekins or oven ready crocks and top with toasted bread and shredded cheese. 
- Add ramekins to the oven and broil until cheese is browned and bubbly. 
- Remove from oven and top with cilantro, green onions, or red pepper flakes, if desired. 
- Serve immediately.