Let’s be brutally honest: Tennessee onions aren’t some meek side dish—they’re a full-flavored symphony that steals every potluck show. Picture this: plump, sweet Vidalias, sliced into half-moons like edible stained glass, weeping their sugars into a molten moat of sharp cheddar. Above, a golden armor of buttery Ritz cracker crumbs shatters under your fork, releasing…