I'm new to Grand Rapids and in my quest to find a great burger, I found a great smashed diner-style burger at Fat Boy Burgers. You can tell by looking at the patty it's hand-formed. Actually, "formed" isn't really the word—it looks like they toss a loose clump of meat on the flat-top and smash it on the flip. They serve crinkle-cut fries, but they're thinner and crisper than the usual.
The "Fat Boy" has olives and mayo on it, but not an insane, goopy amount. It works pretty well. The bun is baked semi-local (its from a bakery a few towns over), and the other toppers (tomato, lettuce) are really well done. (The lettuce is a long shred—angel-hair lettuce would be a good analogy.) The regular burger with mustard, ketchup, and pickle is just as good as the Fat Boy. The patties are so craggy and dark brown and crunchy-yet-tender. It's easily the best burger I've had in GR, but I've got a few more places to try out.
The burgers come in fries and drink combos for about five to six bucks. They've got some great breakfast items as well, but "burgers" is in the name, and deservedly so. It's newly remodeled and reopened in 2009 with a new owner. It has that eclectic look so many local places do. Anyone in town ought to check it out—it's easy to get to and worth a visit.
Fat Boy Burgers
2450 Plainfield Avenue Northeast, Grand Rapids, MI 49505 (map) 616-447-2200