Preheat the Oven:

o Preheat your oven to 375°F (190°C).

Prepare the Vegetables:

o Peel the potatoes and slice them thinly into 1/8-inch rounds. Place them in a bowl of water to prevent browning while you prepare the other vegetables.

o Slice the zucchini into 1/4-inch rounds.

o Thinly slice the red onions into rounds. If the onion is large, cut it in half first before slicing.

Layer the Vegetables:

o Drain the potatoes and pat them dry. In a large baking dish or roasting pan, start by arranging a layer of sliced potatoes, followed by a layer of zucchini, and then a layer of red onion.

o Repeat the layers until all the vegetables are used up, slightly overlapping the slices to ensure even cooking.

Season the Vegetables:

o Sprinkle the minced garlic, dried oregano, dried rosemary, and half of the chopped parsley evenly over the vegetables.

o Season generously with salt and black pepper to taste.

o Drizzle the olive oil over the vegetables, making sure they are well coated. Use a brush or your hands to spread the oil evenly if needed.

Add the Tomatoes:

o Pour the diced tomatoes and their juice evenly over the layered vegetables. Gently press down on the vegetables with the back of a spoon to allow the tomatoes and their juices to settle into the dish.

Bake the Briam:

o Cover the baking dish with aluminum foil and bake in the preheated oven for 45 minutes.

o After 45 minutes, remove the foil and continue baking for another 30-40 minutes, or until the vegetables are tender and slightly browned around the edges. The liquid should be mostly absorbed, and the vegetables should have a rich, roasted appearance.

Finish and Serve:

o Remove the Briam from the oven and let it rest for a few minutes. Sprinkle the remaining chopped parsley over the top before serving.

o Serve warm or at room temperature with crusty bread and a side of feta cheese, if desired.