Looks like a burger, doesn't it? Gotcha! This delicious recipe doesn't have an ounce of meat in it, but it's still as deliciously satisfying. Portobello mushroom tops stand in for the burger patter, and thanks to their hollow shape, get stuffed with fresh spinach and havarti cheese. All you gotta do is grill 'em and stuff 'em while cooking, to meld everything together.