Grease a large casserole dish and place slices of bread in bottom of dish.
Beat the eggs, then add in the mustard, salt, and milk.
Chop vegetables and basil and sprinkle over the bread slices.
Pour over egg mixture, then top with shredded cheese.
Refrigerate for at least an hour.
An hour before dinner, put casserole in oven. Set temperature to 350 degrees. Bake for 50 minutes, or until casserole is golden brown and puffy.