
Crispy smashed baby potatoes are topped with caramelized onions and Gruyère for a bite-sized spin on the beloved classic French onion soup.
In a large skillet over medium heat, melt butter. Add onions and salt and cook, stirring occasionally, until onions are jammy and deep golden brown, 35 to 50 minutes.
Arrange a rack in center of oven; preheat to 450°. In a medium pot, cover potatoes with 1" cold water; generously with 2 Tbsp. kosher salt. Bring to a boil over high heat. Reduce heat to medium-low and simmer until a paring knife slides easily into center (potatoes should be tender but not mushy), about 15 minutes.