Step 1

Preheat oven to 400°F. Cut eggplant into 12, (3/8-in.-thick) slices. Arrange eggplant on a wire rack set in a rimmed baking sheet. Bake in preheated oven until slightly dried out, about 15 minutes. Set aside. Bake in 2 batches, if necessary.

Step 2

Heat a large skillet over medium-high. Add beef to skillet; cook, stirring occasionally to break up chunks, until well browned, 7 to 8 minutes. Add onion, bell pepper, garlic, salt, black pepper, and crushed red pepper; cook, stirring occasionally, until tender, about 4 minutes. Stir in marinara. Reduce heat to medium; cook, stirring occasionally for 10 minutes. Remove from heat.

Step 3

Stir together ricotta and eggs in a small bowl.

Step 4

Spread 1/2 cup meat sauce in bottom of a greased 13- x 9-inch glass baking dish. Arrange 3 pieces of eggplant in a single layer over sauce. Top with 3/4 cup meat sauce, 1/2 cup ricotta mixture, and 4 ounces of shredded mozzarella. Repeat layers 3 more times. Top with fresh mozzarella pieces, and sprinkle with thyme. Cover with aluminum foil, and bake at 400°F for 45 minutes. Remove foil, and bake until top is browned, another 30 to 35 minutes. Remove from oven, and let stand 15 minutes before cutting.