Savory Puff Pastry Tarts with Caramelized Onions and Mushrooms
Please note, this post may contain affiliate links. Visit Devine Fairytale’s Disclosure Policy for more details.
There’s something undeniably captivating about the aroma of buttery, flaky pastry and the mouthwatering flavors of perfectly caramelized onions and earthy mushrooms. These savory puff pastry tarts hit all the right notes with sweet caramelized onions, marinated Portobello mushrooms, Applewood smoked cheddar cheese, and a hint of fresh thyme.

Ingredients
Marinated Mushrooms
8 oz. Baby Portobello Mushrooms, cleaned and sliced
¼ c. Marsala Wine
Sea Salt and Black Pepper, to taste
2 T. Extra Virgin Olive Oil
Caramelized Onions
4 Large Yellow Onions
¼ c. Unsalted Butter
3 T. Dry White Wine
Sea Salt and Black Pepper, to taste
Remaining Ingredients
1 Package Frozen Puff Pastry
2 Eggs, beaten
All-Purpose Flour, for rolling
8 oz. Applewood Smoked Cheddar, grated
3 T. Fresh Thyme Leaves
What You’ll Need
Medium Bowl
2 Skillets
2 Large, Rimmed Baking Sheets
Parchment Paper or Silpat Baking Mats
Pizza Cutter
Cheese Grater
Brush

Instructions
Prep time: 30 minutes
Cook time: 90 minutes
Yield: 64 appetizers
1. In a medium glass bowl, combine mushrooms and Marsala wine. Season with salt and black pepper, to taste. Toss to coat. Marinate for 20 minutes at room temperature. Drain excess moisture before cooking.
2. While the mushrooms are marinating, slice off both ends of each onion and remove the papery outer layers. Cut in half lengthwise (from tip to root) and then slice each half lengthwise into strips. Tip: Don’t slice too thin or they may burn while cooking.
3. Melt butter in a large, high-sided skillet set over medium heat. (For best results, do not use a non-stick pan). Add onions and stir until coated with butter.
4. Cook for approximately 45- 50 minutes, stirring every 5 minutes or so, to ensure the onions cook evenly and don’t stick to the pan. The exact cooking time will vary depending on several factors, including the age of the onions and how many you cook at one time.
5. Once the onions are started, heat 2 tablespoons olive oil in another large skillet over medium-high heat. Once oil is hot, add marinated mushrooms and sauté until browned and tender, approximately 5-7 minutes. Remove from heat and transfer to a bowl. Set aside.
6. Preheat oven to 375°F and line two large, rimmed baking sheets with parchment paper or Silpat™ baking mats. Set aside.
7. When the onions reach the desired depth of color, add white wine to deglaze the bottom of the pan. Add more liquid, if necessary, to scrape up all the brown bits and then salt and pepper the onions, to taste. Remove from heat and set aside.
8. Cut thawed puff pastry dough in half and roll out on a lightly floured surface. With a sharp knife or pizza cutter, cut the puff pastry sheet into 32 equally sized rectangles. (See picture). Transfer puff pastry pieces to a prepared baking sheet and place in the freezer for 10 minutes.

9. Repeat the above steps for the other half of the puff pastry.
10. Remove baking sheets from the freezer and let sit for a couple of minutes before brushing each piece with the beaten egg. Divide the grated cheddar cheese, caramelized onions, and sautéed mushrooms among the puff pastry pieces and top with the thyme.
11. Place baking sheets in the pre-heated oven and bake for 10-15 minutes before rotating each baking sheet to ensure the pastry tarts cook evenly.
12. Continue cooking until the pastry is golden brown, approximately 8-10 minutes. Remove from oven and cool slightly before serving. Enjoy!

Savory Puff Pastry Tarts with Caramelized Onions and Mushrooms
Equipment
- 1 Medium Bowl
- 2 Skillets
- 2 Baking Sheets
- Parchment Paper or Silpat Baking Mats
- Pizza Cutter
- Cheese Grater
- Brush
Ingredients
Marinated Mushrooms
- 8 oz Baby Portobello Mushrooms cleaned and sliced
- 1/4 c Marsala Wine
- Sea Salt to taste
- Black Pepper to taste
- 2 T Extra Virgin Olive Oil
Caramelized Onions
- 4 Yellow Onions
- 1/4 c Unsalted Butter
- 3 T Dry White Wine
- Sea Salt to taste
- Black Pepper to taste
Other Ingredients
- 1 Package Frozen Puff Pastry
- 2 Eggs beaten
- All Purpose Flour for rolling
- 8 oz Applewood Smoked Cheddar grated
- 3 T Fresh Thyme Leaves
Instructions
- In a medium glass bowl, combine mushrooms and Marsala wine. Season with salt and black pepper, to taste. Toss to coat. Marinate for 20 minutes at room temperature. Drain excess moisture before cooking.8 oz Baby Portobello Mushrooms, 1/4 c Marsala Wine, Sea Salt, Black Pepper
- While the mushrooms are marinating, slice off both ends of each onion and remove the papery outer layers. Cut in half lengthwise (from tip to root) and then slice each half lengthwise into strips. Tip: Don’t slice too thin or they may burn while cooking.4 Yellow Onions
- Melt butter in a large, high-sided skillet set over medium heat. For best results, do not use a non-stick pan. Add onions and stir until coated with butter.1/4 c Unsalted Butter, 4 Yellow Onions
- Cook for approximately 45- 50 minutes, stirring every 5 minutes or so, to ensure the onions cook evenly and don’t stick to the pan. The exact cooking time will vary depending on several factors, including the age of the onions and how many you cook at one time.4 Yellow Onions
- Once the onions are started, heat 2 tablespoons olive oil in another large skillet over medium-high heat. Once oil is hot, add marinated mushrooms and sauté until browned and tender, approximately 5-7 minutes. Remove from heat and transfer to a bowl. Set aside.2 T Extra Virgin Olive Oil, 8 oz Baby Portobello Mushrooms
- Preheat oven to 375°F and line two large, rimmed baking sheets with parchment paper or Silpat baking mats. Set aside.
- When the onions reach the desired depth of color, add white wine to deglaze the bottom of the pan. Add more liquid, if necessary, to scrape up all the brown bits and then salt and pepper the onions, to taste. Remove from heat and set aside.3 T Dry White Wine, Sea Salt, Black Pepper, 4 Yellow Onions
- Cut thawed puff pastry dough in half and roll out on a lightly floured surface. With a sharp knife or pizza cutter, cut the puff pastry sheet into 32 equally sized rectangles. (See picture). Transfer puff pastry pieces to a prepared baking sheet and place in the freezer for 10 minutes.1 Package Frozen Puff Pastry, All Purpose Flour
- Repeat the above steps for the other half of the puff pastry.1 Package Frozen Puff Pastry, All Purpose Flour
- Remove baking sheets from freezer and let sit for a couple of minutes before brushing each piece with the beaten egg. Divide the grated cheddar cheese, caramelized onions, and sautéed mushrooms among the puff pastry pieces and top with the thyme.2 Eggs, 8 oz Applewood Smoked Cheddar, 3 T Fresh Thyme Leaves
- Place baking sheets in the pre-heated oven and bake for 10-15 minutes before rotating each baking sheet to ensure the pastry tarts cook evenly.
- Continue cooking until the pastry is golden brown, approximately 8-10 minutes. Remove from oven and cool slightly before serving. Enjoy!
Nutrition
Storage
It takes some time to caramelize the onions, so this recipe is designed to give you plenty of leftovers. Store the unused portion in an airtight container in the refrigerator for up to one week or freeze for later use. Caramelized onions are wonderful on sandwiches, in soups, or on top of your favorite pizza.

Tips for Savory Puff Pastry Tarts
Save time by caramelizing the onions a day or two before preparing this recipe.
Thaw the puff pastry overnight in the refrigerator.
Place cheese in the freezer for 10 minutes before grating for best results.
Don’t overbake the tarts. They should be golden brown and crispy, but not dry.
The bites can be made ahead of time and frozen. This makes them a great option for parties or potlucks.

Variations
If you need a different cheese option, Gruyere would pair well with the onions and mushrooms.
Creating savory puff pastry tarts with caramelized onions and mushrooms is a delightful culinary adventure that yields irresistible results. The combination of flaky pastry and the rich, savory filling of caramelized onions and mushrooms is a true crowd-pleaser. Whether you’re a seasoned chef or a novice in the kitchen, this recipe is accessible and guaranteed to impress. So, roll up your sleeves, gather your ingredients, and embark on a journey to craft these delectable bites that will have your taste buds dancing with joy.

Kelsey
Such a unique recipe! Will definitely be giving it a try
Sharon Rooney
These look delicious and appear super easy to make.
Antoinette M
These look delicious! I love the puff pastry.