You order a smash burger, you order a mess. The patties, yanked off the flattop moments ago, drip scalding juices. Their lacy edges sprawl beyond the bun, obscuring the bottom half like the brim of a bucket cap on a toddler’s head. Somehow, against the laws of physics, the grilled onions have turned as molten and liquid as the cheese.

Do Shaggy’s burger restaurant is photographed on Friday, Dec. 13, 2024. Do Shaggy’s is located at 429 South Church Street in St. Peters.
Still, a smash burger from St. Peters newcomer Do Shaggy’s might surprise you. You’re not experiencing a hunger-induced delusion or reaching for a restaurant critic’s easy adjective. The burgers here really do gleam. The buns are shiny — to the point that I asked whether the cooks brush the tops with butter or something else.
The cooks do not. The buns, to use another critic’s easy adjective, are magical.
Do Shaggy’s opened in February in the shopping plaza at South Church Street and Mexico Road, a short drive from the chaotic interchange of Interstate 70 and Mid Rivers Mall Drive. The storefront is small — dining tables and the counter where you order — but distinctive. Owner Matt Cartwright says the eclectic decor reflects his personality.
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A longtime skateboarder, Cartwright has installed a model skate park on a table by the soda fountain, and the restroom walls are plastered with graffiti. Meanwhile, a banner of Slowpoke Rodriguez, oft-forgotten cousin of second-tier “Looney Tunes†character Speedy Gonzales, hangs on a wall.
(Sadly, as the parent of two Generation Alpha kids, I must report that oft-forgotten now applies to the entire “Looney Tunes†universe. Please drop “The Catcher in the Rye†from the curriculum in favor of “What’s Opera, Doc?â€)

Matt Cartwright, owner and burger chef at Do Shaggy's
Do Shaggy’s is Cartwright’s first restaurant, but he has worked in the industry for more than 20 years. He made his way from busser to management at Outback Steakhouse. At Texas Roadhouse, he went from managing a single restaurant to overseeing multiple locations.
Late last decade, burned out by the travel in his job, Cartwright wanted to plan his own restaurant. By 2019, he was ready to go for it. Then, the pandemic hit. Instead, he decided to study the business of burgers at restaurants including Steak ‘n Shake and Red Robin before opening his own spot.
As for the Do Shaggy’s name, Cartwright drew inspiration from “Scooby-Doo†and his formerly shaggy skateboarder’s hair. Googling revealed that Shaggy’s by itself wasn’t original. He really wanted to “do Shaggy’s†as a name, though. Do Shaggy’s stuck.
The menu features a few signature burgers as well as a build-your-own option. Whatever you choose, each skinny patty holds its form and, even as the grill emblazons it with a crisp, comprehensive char, retains its essential beefiness. (A turkey patty is also available, though I didn’t try one for this review. Currently, there isn’t a non-meat patty.)
The Shaggy’s Original is a classic combination of two patties (the default for Do Shaggy’s signatures), American cheese, grilled onions, pickles and a tangy house sauce. You see the attention to detail in those garnishes. The onions are soft and sweet but still deliver a bite. The pickles snap in texture and flavor.
Likewise, the thick slices of grilled jalapeño available either as a custom option or with Carolina reaper-pepper jack cheese on the Spicy A/F burger burst with fresh, blistering heat. Crucially, Do Shaggy’s patty impresses without a stack of toppings or that cushy, buttery bun. The Flippin Frisco, a tribute to Steak ‘n Shake’s patty melt, simply gilds twin patties with Swiss and American cheeses and Thousand Island dressing between crunchy golden slices of griddle-toasted bread.
Cartwright keeps Do Shaggy’s menu focused, but while burgers are the obvious star here, Cartwright ventures into the chicken sandwich wars with a winning example. Marinated, hand-breaded and deep-fried — and, in my case, tossed with piquant buffalo sauce — the thin, broad cutlet yields juicy meat under its gnarled exterior.

The Cheesesteak, a sandwich served at Do Shaggy’s.
The Cheese Steak Mafia shows promise, not merely spilling out of its garlic hoagie roll, but causing its immediate collapse when I tried to pick it up. Yet for its generous serving of shaved, grilled steak with provolone, peppers and onions, I was a little too aware of how much mayonnaise had been slathered on the sandwich.
The burgers and sandwiches are priced a la carte, but you can upgrade to a meal with a fountain drink and side of either good, straightforward fries or better, very crispy onion rings for $4.50 or $5 more, respectively. A house salad is also available as a side, but if you’re going to eat at Do Shaggy’s, you might as well truly Do Shaggy’s.
The ninth edition of the STL100, a list of the best restaurants in the ¹û½´ÊÓÆµ area, brought both familiar and new names. Check out the top 10, then find the full list on our website.