Preheat oven to 375 degrees F. Line a rimmed baking sheet with aluminum foil.
In a large bowl, place the potatoes, onions, bell peppers, and garlic cloves. Toss the vegetables with the olive oil, salt, pepper, and thyme. Cover and let sit for approximately 3 to 4 hours, giving them a toss now and then and adding more oil oil if needed. You want a light coating on all the vegetables.
Bake approximately 45 minutes, turning occasionally. You want the vegetables to begin to caramelize their sugars. The edges will start to turn brown.
When the vegetables are finished cooking, remove from the oven. Drizzle with a little balsamic vinegar or balsamic reduction over the top of all the vegetables.
Place on a serving dish and serve.
Makes 6 to 8 servings as a side dish.
* Learn how to make a balsamic reduction or Faux Aged Balsamic Vinegar.
Roasted Rainbow Potatoes Recipe: https://whatscookingamerica.net/karencalanchini/roastedrainborpotatoes.htm