Photo: Alison Gootee; Styling: Suzonne Stirling
These elegant looking little appetizers are surprisingly easy to make, thanks to store-bought puff pastry. Caramelizing the onions is the most difficult step, and only requires stirring, and patience. Don’t rush this process; you want to coax out as much sweetness as possible out of the onions. You can make these up to two-days in advance. Prepare the unbaked bites, cover, and place them in the refigerator. Bake as directed when ready to serve.
How to Make It
Step 1
Heat butter and olive oil in a heavy-bottomed saucepan over medium until butter is melted. Add sliced onions all at once; stir to coat. Cook, undisturbed, until onions begin to soften, about 4 minutes. Add thyme, mustard, pepper, salt, and sugar; stir to combine. Cook, covered, stirring every 4 minutes, until onions begin to brown, break down, and resemble onion jam, about 16 minutes. Reduce heat if onions begin to brown too quickly.
Step 2
Add chicken stock to pan. Cook, stirring constantly with a wooden spoon to loosen browned bits from bottom of pan, until liquid evaporates, about 30 seconds. Remove pan from heat, and let stand while pastry bites are assembled.
Step 3
Preheat oven to 375°F with rack in upper third of oven. Unfold thawed puff pastry on a lightly floured work surface. Use a rolling pin to roll out 1 sheet, creating a 10-inch square. Repeat with second sheet.
Step 4
Spoon 25 dollops (about 1 teaspoon each) of onion filling about 1 inch apart on 1 of the pastry sheet squares (5 individual teaspoons on each of 5 horizontal rows and 5 teaspoons on each of 5 vertical rows). Top each teaspoon of onion filling with a pinch of shredded Gruyère.
Step 5
Carefully place remaining pastry sheet square on top of onion- and cheese-topped square. Gently press pastry around onion-and-cheese filling to seal. Use a pizza cutter to slice into 25 pastry bites. Use a fork to press edges of each to seal in filling
Step 6
Place pastry bites about 2 inches apart on a baking sheet lined with parchment paper. Lightly brush each with egg, and sprinkle with salt and pepper.
Step 7
Bake in preheated oven until golden brown and puffed, 12 to 15 minutes. Remove from oven; let cool 15 minutes before serving. (Unbaked bites can be made ahead, covered, and refrigerated up to 2 days or frozen up to 2 weeks ahead; bake at 375°F for 15 to 20 minutes.) Serve the puff pastry bites with Dijon and grainy mustards on the side for dipping.
