These Cheesy Mushroom Puff Pastry Bites are a sophisticated and incredibly delicious appetizer, perfect for any holiday gathering or special occasion. Flaky, buttery puff pastry is topped with a layer of tangy mustard, sweet caramelized onions, earthy mushrooms, and melted Gruyère cheese. Each bite is a perfect combination of savory, creamy, and crispy.
They look elegant and taste like they came from a gourmet bakery, but they are surprisingly simple to assemble. These bites are a guaranteed showstopper that will disappear quickly from any party platter.
Why You’ll Love This Cheesy Mushroom Puff Pastry Bites
These Cheesy Mushroom Puff Pastry Bites are a masterclass in flavor and texture. The buttery, flaky pastry provides the perfect base for the rich, savory filling of sweet caramelized onions, earthy mushrooms, and nutty Gruyère cheese. The tangy mustard adds a surprising and delightful kick that ties everything together.
They look and taste incredibly impressive, yet they are quite simple to prepare. This is a versatile recipe that is sure to become a favorite for all your special occasions.
Ingredients
- 2 tablespoons extra virgin olive oil, divided
- 1 large yellow onion, thinly sliced
- ½ teaspoon kosher salt
- 16 ounces baby bella mushrooms, sliced
- ½ teaspoon minced garlic
- 2 teaspoons finely chopped fresh thyme leaves (or ½ teaspoon dried)
- ¼ teaspoon ground black pepper
- ½ cup shredded Gruyère, Swiss, or similar cheese (about 1½ ounces)
- 2 (10-inch square) sheets frozen puff pastry, thawed
- 1 egg, beaten
- 3 tablespoons whole-grain mustard
- Chopped fresh parsley, for garnish
Step-by-Step Method
Step 1: Caramelize the onions
In a large skillet, heat 1 tablespoon of olive oil over medium-low heat. Add the thinly sliced onion and kosher salt. Cook slowly, stirring occasionally, for 15-20 minutes, until the onions are soft, sweet, and deeply golden brown. Once caramelized, remove them from the skillet and set aside.
Step 2: Cook the mushrooms
In the same skillet, heat the remaining 1 tablespoon of olive oil over medium-high heat. Add the sliced mushrooms and cook, stirring occasionally, until they have released their liquid and started to brown, about 8-10 minutes. Stir in the minced garlic, thyme, and black pepper, and cook for another minute until fragrant.
Step 3: Combine the filling
Return the caramelized onions to the skillet with the mushrooms. Stir to combine, then remove from the heat. Let the mixture cool for a few minutes before stirring in the shredded Gruyère cheese.
Step 4: Prepare the puff pastry
Preheat your oven to 400°F (200°C). Line two baking sheets with parchment paper.
Unfold the thawed puff pastry sheets on a lightly floured surface. Cut each sheet into 9 equal squares. You will have 18 squares in total. Place the squares on the prepared baking sheets.
Step 5: Assemble the bites
Using a fork, prick the center of each pastry square a few times, leaving a small border around the edges. Brush a thin layer of whole-grain mustard inside the pricked area of each square.
Spoon a portion of the mushroom and onion mixture onto the center of each square. Brush the edges of the pastry with the beaten egg wash for a golden, shiny finish.
Step 6: Bake and serve
Bake for 15-18 minutes, or until the puff pastry is puffed up, golden brown, and the cheese is melted and bubbly.
Let the bites cool for a few minutes on the baking sheet before transferring them to a serving platter. Garnish with chopped fresh parsley and serve warm.
Expert Tips for Success
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Thaw puff pastry properly: For the best results, thaw puff pastry in the refrigerator overnight.
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Don’t skip caramelizing: Taking the time to slowly caramelize the onions adds a deep, sweet flavor that is essential to the dish.
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Cook the mushrooms well: Make sure the mushrooms have browned and their liquid has evaporated to prevent the pastry from becoming soggy.
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Don’t overfill: A small amount of filling goes a long way. Overfilling can make the pastry heavy and prevent it from puffing properly.
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Egg wash is a must: It gives the pastry a beautiful, glossy, golden-brown finish.
Tasty Variations to Try
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Different cheeses: Try goat cheese, fontina, or even a sharp white cheddar.
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Add a little wine: Deglaze the pan with a splash of dry white wine after cooking the mushrooms for an extra layer of flavor.
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Meaty addition: Add some crispy, crumbled turkey bacon or prosciutto to the filling.
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Herb variations: Swap thyme for fresh rosemary or sage.
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Balsamic glaze: A drizzle of balsamic glaze over the finished bites adds a lovely tangy sweetness.
Serving Ideas
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Elegant appetizer: They are the perfect starter for a holiday dinner or a fancy get-together.
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Paired with wine: Serve them with a glass of crisp white wine or a light-bodied red.
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On a brunch buffet: These savory bites are a wonderful addition to a brunch spread.
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As a side: They can be served alongside a steak or a roast chicken for a special meal.
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Party finger food: Their individual size makes them perfect for mingling.
Frequently Asked Questions
Can I make these ahead of time?
Yes. You can assemble the bites (without baking) and store them in the refrigerator for up to a few hours. Bake them just before you’re ready to serve.
How do I store leftovers?
Store leftovers in an airtight container in the refrigerator for up to 3 days.
What’s the best way to reheat these?
Reheat them in an oven or air fryer at 375°F (190°C) for 5-7 minutes until they are warm and the pastry has re-crisped.
Can I use different types of mushrooms?
Yes, cremini, shiitake, or a wild mushroom blend would all be delicious.
Can I freeze these bites?
It’s best to freeze them unbaked. Assemble them on a baking sheet, freeze until solid, then transfer to a freezer-safe bag. You can bake them from frozen, adding a few extra minutes to the baking time.
Print
Cheesy Mushroom Puff Pastry Bites
- Total Time: 50
- Yield: 18 bites 1x
- Diet: Vegetarian
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
- 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
