Ingredients

• 6 medium yellow onions, thinly sliced
  
• 3 tablespoons unsalted butter
  
• 3 (10 1/2 oz) cans condensed beef bouillion (undiluted)
  
• 2 cups water
  
• 2 tablespoons brandy (cognac)
  
• 14-16 slices french bread (about 2 small loaves)
  
• 1 cup parmesan cheese, grated
  
• 1/2 pound imported swiss cheese, grated