Name: Mushroom Puff Pastry Bites
Prep time: 20 min
Cook time: 25 min
Total time: 45 min
Cuisine: French-Inspired
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 finely chopped fresh thyme (or ½ tsp dried thyme); ¼ tsp ground black pepper; ½ cup shredded Gruyere or Swiss cheese (about 1 ½ oz); 2 sheets frozen puff pastry (10-inch square, thawed); 1 egg, beaten; 3 tbsp whole-grain mustard; Chopped fresh parsley, for garnish

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Mushroom Puff Pastry Bites are a golden, flaky, and savory appetizer that’s elegant enough for a party yet simple to make. Caramelized onions, earthy mushrooms, fresh herbs, and melty cheese come together inside buttery puff pastry for an irresistible bite-sized treat.

Why You’ll Love This Recipe

Impressive yet easy-to-make appetizer
Perfect for holidays, parties, or casual gatherings
Can be made ahead and reheated for convenience
Rich, savory flavors with a balance of caramelized onions and mushrooms
Vegetarian-friendly but hearty enough to satisfy everyone
Crispy, flaky, and golden puff pastry for the perfect bite

Ingredients

(Tip: You’ll find the full list of Ingredients and measurements in the recipe card below.)

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 thyme)
¼ teaspoon ground black pepper
½ cup shredded Gruyere, Swiss, or similar cheese (about 1 ½ ounces)
2 sheets frozen puff pastry (10-inch square, thawed)
1 egg, beaten
3 tablespoons whole-grain mustard
Chopped fresh parsley, for garnish

Directions

Preheat oven to 400°F (200°C). Place racks in the upper and lower thirds of the oven and line two baking sheets with parchment paper or silicone mats.
In a large skillet over medium-low heat, warm 1 tablespoon olive oil. Add onion and salt, sauté until golden and caramelized, about 25 minutes, stirring occasionally. Transfer to a bowl.
In the same skillet, add remaining olive oil and mushrooms. Cook over medium-low until tender, about 5 minutes. Stir in garlic, thyme, and black pepper, cooking for 1 more minute. Add to the onions. Stir in shredded cheese.
On a lightly floured surface, roll puff pastry into a 10.5-inch square. Cut into 2-inch rounds using a cookie cutter (or slice into squares to reduce waste). Each sheet yields about 25 rounds.
Transfer pastry rounds to baking sheets. Brush lightly with beaten egg and prick each with a fork.
Top each round with ¼ teaspoon mustard and 1 tablespoon of mushroom-onion mixture. Repeat with second pastry sheet.
Bake for 25 minutes, rotating pans halfway through, until golden and crisp. Let cool for 5 minutes. Garnish with fresh parsley and serve warm or at room temperature.

Servings and timing

Servings: About 50 bites
Prep time: 20 minutes
Cook time: 25 minutes
Total time: 45 minutes

Variations

Cheesy Swap: Try sharp cheddar, Fontina, or Parmesan instead of Gruyere.
Herbal Twist: Use rosemary or sage in place of thyme for a different flavor.
Mini Tart Style: Bake in mini muffin tins instead of cutting rounds.
Sweet-Savory Version: Add a drizzle of balsamic glaze after baking.
Meaty Addition: Mix in cooked crumbled bacon or sausage with the mushroom filling.

Storage/Reheating

Refrigerate: Store in an airtight container in the fridge for up to 2 days.
Reheat: Warm in a 400°F oven for 3–5 minutes until crisp.
Freeze: Bake bites fully, cool, and freeze in layers separated with parchment for up to 2 weeks. Reheat from frozen at 400°F for 5 minutes.
Make Ahead: Prepare topping up to 2 days ahead, refrigerate, then assemble and bake when ready.

FAQs

Can I use store-bought puff pastry?

Yes, store-bought puff pastry works perfectly for this recipe.

Do I need to thaw puff pastry before using?

Yes, thaw in the fridge overnight or at room temperature for about 30 minutes.

Can I caramelize onions faster?

You can cook them over higher heat, but low and slow gives the best flavor.

Can I use other types of mushrooms?

Yes, cremini, shiitake, or white button mushrooms all work well.

Can I skip the mustard?

Yes, but it adds tang and balances the richness of the filling.

How do I keep the bites from getting soggy?

Pricking the pastry with a fork before topping helps vent steam and keep them crisp.

Can I make them in advance?

Yes, bake fully and reheat before serving, or prep filling ahead to save time.

Can I serve these cold?

They are best served warm, but can be enjoyed at room temperature.

Can I make these gluten-free?

Yes, use gluten-free puff pastry available in specialty stores.

What’s the best way to cut the pastry rounds?

A 2-inch cookie cutter works best, but you can cut squares with a knife to avoid waste.

Conclusion

Mushroom Puff Pastry Bites are a versatile, elegant, and crowd-pleasing appetizer perfect for any gathering. With their rich caramelized onion and mushroom filling, cheesy flavor, and buttery crisp pastry, they’re bound to be the first dish to disappear at your table.

Maggie