You want a great burger, but you start with supermarket ground beef (because who wants to grind their own?). That presents two problems: virtually flavorless meat and a burger that's tough and dense because pre-ground beef binds together like glue.

How, then, to make a great burger with store-bought ground beef? We found the answer 1,500 miles south of Milk Street, in Miami.

The spatula-wielding line cook at El Mago de la Frita smashes three fistfuls of beef against a hot flat-top. The raw meat is spiked with so much seasoning, the patties are bright orange.

The cook sprinkles each with grated raw onion, then squirts them with a watery red sauce. A moment later, he flips the patties, placing a soft bun on top of each as they cook. The pale buns sop up the sauce, taking on its tangerine hue.

The sauce doesn't have a name, but it's a blend of tomato paste, water, garlic, hot sauce, and the same seasonings that give this burger its distinctive coloring: Spanish smoked paprika and cumin — typical Cuban spices.

Miami's Cuban culture pervades the city, in its food as well as its music. (Connie Miller of CB Creatives & Justin Namon/RAHAUS | Courtesy Christopher Kimball's Milk Street)

The thin patties are done in three minutes. The cook slides the spatula under each, holding the bun down, and flips them off the grill. He tops one with an egg, one with Swiss, and all of them with a heap of shoestring potato fries. A top bun is all that's needed to complete the super-seasoned sandwich.

This is a frita, often dubbed the Cuban hamburger. It began as street food in Havana in the 1930s, then migrated to Miami in the 1960s. Today, South Florida may be the only place to get a real one.

Biting into El Mago's frita, it wouldn't be far-fetched to think you were tasting chorizo. But the patty is 100 percent beef — it's all in the seasoning. And that's how it was in Cuba, too, El Mago employee Barry Hennessey says. "In the 1900s, there wasn't enough money to spend on Spanish chorizo."

"Wealth changes how we dine," Hennessey says of the frita and its aggressive spicing. "Cumin was used to hide bad meat ... the same as in the East, where you use curry."

Back at Milk Street, the frita had given us a solution for our first problem — flavoring store-bought ground beef. We tested varying levels and combinations of spice, ultimately landing on even amounts of Spanish smoked paprika and cumin, plus salt and pepper.

Smoked paprika and cumin give the Cuban frita its chorizo-esque flavor. (Connie Miller of CB Creatives & Justin Namon/RAHAUS | Courtesy Christopher Kimball's Milk Street)

But when we mixed the spices into the meat with our hands, the resulting patties were dense and compact.

It's an inherent problem with pre-ground beef. Because 85 percent of meat's moisture is contained in its muscle fibers, much of it is released during grinding. One protein in beef, myosin, literally dissolves in those juices, creating what's called "sticky protein." The sticky protein acts as a kind of glue, binding small pieces of meat together. More mixing releases more moisture, leading to more sticky protein and a tougher burger.

Ironically, the solution to our store-bought beef problem came from the method for grinding your own meat. In order to grind meats without getting too much sticky protein, butchers thoroughly chill their meat to ensure the muscle and fat will be firm when they go through a grinder's blades. We wondered if we could adapt the technique for mixing together our pre-ground beef before forming patties.

So we used two forks to gently spread the beef in a thin layer on a baking sheet before sprinkling paprika, cumin, salt, and pepper over it. Spreading sped up chilling and gave us more surface area to season.

Then we chilled the meat in the freezer for 20 minutes. That time in the freezer, it turned out, helped to diminish the solubility of the myosin in the juices, reducing the stickiness of the meat. After we took the beef out of the freezer, we folded in the seasonings and then gently formed loose patties. (Depending on the freezer, we sometimes needed to let the beef soften for 10 or 15 minutes before shaping the patties.)

On a hot grill, the burgers cooked to a tender, juicy medium-rare in about 10 minutes, with warm, smoky flavor from the Spanish paprika and cumin. But something was missing: a secret sauce.

So we combined ingredients from El Mago's frita and its sauce (onion, garlic, paprika, cumin, tomato paste, hot sauce, ketchup, and water), added some of our own devising (butter and molasses) and reformulated them to make a thick sauce that balanced heat with a rich, ketchupy sweetness. Slathered on a bun and sandwiched together, the homemade condiment made the perfect match for our smoky, savory Cuban-spiced burger.

For the recipe and more, head to Christopher Kimball's Milk Street.