Toss the onion, garlic, sun-dried tomatoes, 1 tablespoon of the olive oil, 1/2 teaspoon of the thyme, 1/2 teaspoon salt and a couple grinds of pepper in a microwave-safe 9-inch pie dish. Cover with a piece of wax paper. Microwave on high (at 100 percent power) until the onions are soft and translucent, 7 minutes in an 1,100-watt oven or 10 minutes in a 700-watt oven. (When removing the wax paper, be careful to avoid the hot steam.) If the onions are still a little raw, microwave again, covered, in 30-second increments.
While the onions cook, toss the eggplant, zucchini and yellow squash slices with 2 tablespoons of the remaining olive oil, the remaining 1/2 teaspoon thyme, 1/2 teaspoon salt and a few turns of black pepper in a large bowl. Add the plum tomato slices, and gently toss.
Alternating vegetables, shingle slices in a circular pattern over the cooked onions in the pie dish. Sprinkle lightly with salt. Cover with wax paper. Microwave on high (at 100 percent power) until the vegetables are soft, 9 minutes in an 1,100-watt oven or 14 minutes in a 700-watt oven. If there is any resistance when you pierce the vegetables with a paring knife, microwave again, covered, in 30-second increments. Microwave, uncovered, on high (at 100 percent power) for 3 minutes in an 1,100-watt oven or 4 minutes in a 700-watt oven to evaporate excess moisture. Drizzle with the remaining tablespoon of olive oil.
Copyright 2014 Television Food Network, G.P. All rights reserved.