Spread bread cubes on a baking sheet.
Bake at 400°F for 6-8 minutes or until dried (do not brown); set aside.
Meanwhile, in a large skillet, cook the onions, salt and pepper in oil over medium-high heat until onions begin to brown.
Stir in radicchio; remove from the heat.
In a large bowl, combine the bread cubes, radicchio mixture, chicken broth, pancetta, eggs and rosemary; gently toss.
Transfer to a greased 13-in. x 9-in. baking dish and sprinkle with cheese.
Bake, uncovered, at 400°F for 25-30 minutes or until golden brown.