Spray 9x13" glass baking dish with vegetable spray.
Cover bottom of casserole with layer of bread, cutting pieces to fit.
Sprinkle 1/2 prosciutto over bread.
Sprinkle 1/2 goat cheese and 1/2 provolone over prosciutto.
Sprinkle with green onions, basil, roasted garlic, and sun dried tomatoes.
Layer second layer of bread.
Add remaining prosciutto, goat cheese, and provolone.
Use remaining bread cubes on top.
Blend half and half, eggs, mustard, salt, and pepper until well blended.
Pour over casserole.
Pour melted butter over top.
Bake at 350 degrees, uncovered, about 60 minutes.
Remove and let casserole rest for 10 minutes, then broil until top is lightly browned. Cut in squares and serve.