Slow cooker French onion and beef soup

Slow cooker French onion and beef soup 
(The-Skipper-Bunch)

4 med sweet onions; thinly sliced
3 cloves garlic, minced
4 Tbsp butter
2 Tbsp balsamic Vinegar
1 Tbsp Worcestershire
2 Tbsp brown sugar
3 Tbsp Flour
1c beer
6c beef stock
2 Tbsp fresh thyme, chopped
salt and pepper to taste
1-2lb beef roast
French bread, thick sliced
shredded or sliced grueyere or Swiss cheese

----Turn slow cooker onto high. Place butter in the bottom. After it heats up add onion, garlic, vinegar, Worcestershire and brown sugar. Stir well to coat; cover and cook in high for 1hr. Add flour and stir to coat. Let sit for 5I min. Nestle roast in the onions and add remaining ingredients except bread and cheese. Cook 8-12in hrs until meat is falling apart. Remove roast and shred, return to Crockpot. To Serve: Preheat broiler. Ladle soup 3/4 full into oven proof bowls, place onto a baking sheet. Top each bowl with a slice of bread and generously with cheese. Broil in oven until cheese melts and is holden.