Heat broiler. Bring large pot of lightly salted water to boiling for pasta.

Heat 2 tablespoons olive oil in large skillet over medium-high heat. Add sweet peppers and onion; saute 10 to 12 minutes or until tender. Season with 1/2 teaspoon salt and 1/8 teaspoon black pepper. Set aside.

While peppers are cooking, heat remaining 1 tablespoon olive oil in small saucepan. Add garlic; cook over medium-low heat until softened, about 3 minutes. Add marinara sauce, 1/4 teaspoon salt, the sugar, Italian seasoning and red-pepper flakes; cook over medium heat for 5 minutes.

Season the steak on both sides with the remaining salt and black pepper.

Broil steak for about 4 minutes on each side for medium-rare. Remove steak from broiler and let rest for 5 minutes. Slice steak across the grain into 1/2-inch-thick slices. Lower the oven temperature to 400 degrees F.

Cook the linguine in the pot of boiling water following the package directions. Drain well.

Place the sliced meat in glass baking dish. Spoon about 1-1/2 cups of the sauce over the meat. Arrange half the peppers and onions over the sauce; sprinkle with the shredded mozzarella cheese.

Bake in 400 degree F oven until the cheese melts and the meat and pepper mixture is heated through, 4 to 5 minutes.

To serve, toss cooked pasta with remaining pepper mixture and remaining 1-1/2 cups sauce; place on platter. With large spatula, lift the steak slices out of the dish and place over the top of the pasta. Serve with grated Parmesan cheese, the crusty Italian bread and the Caesar salad.