French Onion Smashed Potatoes

Caramelized Onions

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.

Add thyme and wine and cook, stirring and scraping up bits from bottom of pan, until liquid is reduced and onions are jammy, 1 to 2 minutes; season with pepper. Let cool slightly.

Make Ahead: Onions can be caramelized 3 days ahead. Let cool, then transfer to an airtight container and refrigerate. Return to room temperature before using.

Smashed Potatoes

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.

Drain potatoes and return to pot. Cook over low heat, shaking pot occasionally, until potatoes are dry, about 30 seconds.

On a bare metal baking sheet, toss potatoes with 2 Tbsp. oil; season with 1/2 tsp. salt. Spread in an even layer. Using the bottom of a heavy-bottomed glass or measuring cup, lightly smash each potato to 1/2" thick.

Roast potatoes until crispy and golden brown on the bottom and edges, 20 to 25 minutes. Top potatoes with caramelized onions and Gruyère. Continue to roast until cheese is melted, 3 to 4 minutes more.

Top with thyme leaves; season with pepper.