Preheat oven to 325 degrees. Dribble 1 tablespoon of olive oil into a 2-quart rectangular or 14-inch-by-8-inch-by 2-inch oval baking dish and scatter 1/4 of the minced garli cover the bottom of the pan.
Arrange the vegetables in layers, starting with the potatoes and peppers and finishing withthe tomatoes and onion.
Sprinkle salt,freshly ground pepper, and oregano and about 1/4 of the garlic between each layer.
Drizzle the remaining olive oil over the surface and bake for 1 1/2 hours or until fork-tender.
Note: The easiest way to slice the potatoes is with a mandoline. Remember that the thicker the potato slices, the longer it will take to bake.