Preheat the oven to 350 degrees. Prepare two 9x13 baking dishes with nonstick cooking spray.
In a saucepan or small skillet over medium-high heat, saute the onions and celery in butter until softened, about 5 minutes.
In a large mixing bowl, beat together the cream cheese, eggs, and seasonings until the eggs and cream cheese are well blended.
To the mixing bowl, add the vegetables, crab, and parmesan cheese.
Transfer the mixture to the prepared baking dish.
Top the casserole with the mozzarella cheese and the sliced almonds.
Bake for 30 to 35 minutes or until the eggs are completely set in the middle.
Allow the casserole to rest for 5 minutes before slicing and serving.