Make shells and set aside

Preheat the oven to 375 ?F

In a blender or food processor, puree the tomatoes for 10 to 15 seconds

Set aside

Heat olive oil in a heavy 10-inch skillet over moderate heat for one minute; add the onion and cook uncovered, until soft, about 5 minutes

To crush fennel seeds and release aroma, place in a piece of plastic wrap and pound with a rolling pin or bottle

Add the tomatoes, tomato sauce, garlic, oregano, basil, fennel seeds, and pepper

Bring to a boil, reduce the heat to low, and simmer, uncovered, for 10 minutes, stirring often, until the sauce has thickened slightly

Meanwhile, cook the shells until al dente

Rinse with cold water, drain well, and place in an ungreased shallow 3-quart casserole

Cover with the sauce and sprinkle with the mozzarella and Parmesan cheeses

Bake, uncovered, for 30-35 minutes or until bubbly and golden

Let stand for 5 minutes before serving.