Description
Elegant, savory appetizers with flaky puff pastry topped with caramelized onions, earthy mushrooms, and melted Gruyère. Surprisingly simple and perfect for any holiday party or special occasion.
Ingredients
Scale
- 2 tbsp extra virgin olive oil, divided
- 1 large yellow onion, thinly sliced
- ½ tsp kosher salt
- 16 oz baby bella mushrooms, sliced
- ½ tsp minced garlic
- 2 tsp chopped fresh thyme (or ½ tsp dried)
- ¼ tsp ground black pepper
- ½ cup shredded Gruyère or Swiss cheese
- 2 (10-inch square) sheets frozen puff pastry, thawed
- 1 egg, beaten
- 3 tbsp whole-grain mustard
- Chopped fresh parsley, for garnish
Instructions
- Heat 1 tbsp oil in a skillet over medium-low. Add onion and salt; cook slowly for 15-20 minutes until soft and golden brown. Set aside.
- In the same skillet, heat remaining oil over medium-high. Add mushrooms and cook 8-10 minutes until browned. Stir in garlic, thyme, and pepper for 1 minute.
- Return onions to skillet, stir to combine, and remove from heat. Cool slightly, then mix in Gruyère cheese.
- Preheat oven to 400°F (200°C). Unfold pastry on a floured surface and cut each sheet into 9 squares. Place on parchment-lined sheets.
- Prick the center of each square with a fork, leaving a border. Spread a thin layer of mustard inside the pricked area. Spoon mushroom mixture into the center. Brush edges with beaten egg.
- Bake for 15-18 minutes until puffed and golden. Cool slightly, garnish with parsley, and serve warm.
Notes
Thaw puff pastry overnight in the refrigerator for best results.
Slowly caramelizing onions is key for a sweet, deep flavor.
Cook mushrooms until all liquid evaporates to prevent soggy pastry.
Use the egg wash for a beautiful, glossy golden-brown finish.
Assemble bites ahead and refrigerate; bake just before serving.
- Prep Time: 25
- Cook Time: 25
- Category: Appetizer
- Method: Baking
- Cuisine: French-Inspired
Nutrition
- Serving Size: 2 bites
- Calories: 275
- Sugar: 2g
- Sodium: 320mg
- Fat: 17g
- Saturated Fat: 6g
- Unsaturated Fat: 10g
- Carbohydrates: 23g
- Fiber: 2g
- Protein: 6g
- Cholesterol: 30mg
Keywords: mushroom puff pastry, gruyere mushroom bites, savory pastry appetizer, caramelized onion tartlets, holiday finger food