INGREDIENTS
2 tbsp
butter
4 larges
onions
1 pinch
a of salt and pepper to season
2 tsp
thyme
2 tbsp
balsamic vinegar
2 cloves
garlic
1/2 cup
beef broth
1 tbsp
olive oil
4
chicken breasts
2 tsp
garlic powder
1 tsp
ground thyme
1 cup
gruyère
4 tbsp
parmesan