Preheat oven to 400°.
Lightly grease a 9-inch square casserole dish.
Mix together crab, both cheeses and onions in casserole dish.
Sprinkle macadamia nuts over mixture.
Combine remaining ingredients; beat with a hand mixer for 1 minute. Pour into casserole dish.
Bake 35-40 minutes until golden brown and knife inserted into center comes out clean. Let stand 5 minutes before cutting.