Tomato quiche with balsamic caramelized onions

Name: Tomato quiche with balsamic caramelized onions
Prep time: 15 min
Cook time: 1 h 30 min
Total time: 1 h 45 min
Cuisine: American
Ingredients: 1 pie crust (homemade or store bought); 2 onions (halved and sliced thin); 3 tbsp butter; ½ tsp salt; 2-4 sprigs of fresh thyme (use 1tsp of dry thyme if you don't have fresh); 3 tbsp balsamic vinegar; 2-3 tomatoes (depending on their size; sliced. I used one large heirloom and one regular sized yellow gold tomato.); 8 eggs; 3/4 cup heavy cream; 1 ½ tsp salt; Black pepper to taste; 1/8 tsp cayenne pepper (optional); ½ cup parmesan cheese (use a real parmesan if you can, not Kraft); 2 tbsp fresh basil (chopped); 2 tbsp fresh sage (chopped)