I don't like the idea of flattening later for 2 reasons. First, I like the crispy crust, so you get less of that. Then, you would have to flatten the cake w/a spatula since it's hot. I'd be afraid of breaking up the crab, and you're losing the butter and natural juice. I gently level off the top of the mixture after it's all combined, and just eye about 1/4, scoop it out of the bowl with your palm, and it almost a patty/cake. Almost no flattening or forming is needed.