01 -
Preheat the oven to 375°F and lightly oil a 9-inch round baking dish or similar 2-quart capacity dish.
02 -
Select a thin, long eggplant such as Japanese or slender Italian variety and slice it, along with zucchini, yellow squash, tomatoes, and red bell pepper (if using), into uniform 1/8 inch thick rounds using a sharp knife or mandoline.
03 -
Spread vegetable slices flat on sheet pans or cutting boards. Sprinkle evenly with thyme, oregano, salt, and black pepper. Allow to rest for 10 to 15 minutes to draw out excess moisture for better roasting.
04 -
Combine minced garlic with 2 tablespoons olive oil and brush lightly over both sides of all vegetable slices to enhance flavor adherence.
05 -
Dissolve the vegetable bouillon in 2 tablespoons of hot water until fully smooth. Stir into marinara sauce and taste to adjust saltiness before layering.
06 -
Spread the marinara mixture evenly over the bottom of the prepared baking dish. Arrange the vegetable rounds in an upright, overlapping pattern tightly packed to prevent steaming.
07 -
Drizzle the remaining 1 tablespoon of olive oil over the arranged vegetables to promote browning and a glossy finish.
08 -
Cover the dish with a parchment paper layer placed directly over the vegetables, then loosely cover with foil to trap steam without sticking. Bake for 35 minutes.
09 -
Remove the foil and parchment and bake uncovered for an additional 15 to 20 minutes until vegetables are tender and edges caramelize. Let rest uncovered for 10 minutes before serving to allow juices to thicken.