My go-to appetizer/hors d'oeuvre/potluck contribution of late has been a simple caramelized onion tart made on a buttery tart dough. It's good, but when the first of the autumnal cranberries showed up at the market recently, I thought they could add a nice, tart punch to an otherwise rich little bite. With puff pastry on hand, I used it as an easy, convenient base.
Be sure to take your time with the caramelized onions. It's tempting to jack up the heat a bit, but low, slow cooking is the way to make them super sweet and beautifully brown. —vvvanessa
1 1/2 pounds
sweet yellow onions (about 2 very large), very thinly sliced
fresh thyme (lemon thyme is especially good)
In a large skillet, heat the onions, butter, and olive oil over medium-high heat. Cook, stirring constantly, about 5 minutes until the onions begin to shrink down a bit.
Lower the heat to medium-low. Stirring every few minutes, caramelize the onions for 30 minutes. Add in the sprigs of thyme and continue to cook for another 5 minutes, still stirring regularly and lowering the heat as necessary, until the onions reach a uniform toasty brown color. Cooking them slowly over a low heat will help make the onions sweet and evenly browned, so take your time.
Remove the onions from the heat. Carefully remove the thyme stems. Stir in the sour cream or crème fraîche.
Preheat the oven to 400ºF. Directly on a Silpat or on parchement paper, roll out the pastry sheet to about 12 inches by 8 inches. Score the sheet into 2-inch by 2-inch squares. Place the Silpat or parchment on a baking sheet.
Top each square with a heaping tablespoon of the caramelized onions. Place a whole cranberry atop each mound of onions.
Sprinkle salt and fresh pepper very lightly over the squares. Bake for about 15 minutes, rotating the pan about halfway through cooking. The bites are done when the edges of the puff pastry have browned and the cranberries have shrunken.
Cool for 10 minutes on the baking sheet. Serve warm or at room temperature.