Gouda Caramelized Onion Puff Pastry Tart

A herby caramelized onion mixture spread onto crispy, flaky puff pastry and topped with melty Gouda cheese for a flavorful and easy to make dinner or Holiday appetizer (depending on whether you want to share or not).

If you love this onion puff pastry tart, try our other appetizer recipes, like Big Mac Dip and Corn Dog Nuggets.

This caramelized onion puff pastry tart is a delicious dinner or Holiday appetizer. I love serving this onion tart all December long as a Christmas appetizer. It’s delicious, easy to make, and perfect for sharing.

With the caramelized onions and cheese, it sort of has French onion vibes, but as a tart. The flaky golden brown pastry, jammy onions, flavorful cheese, and herby thyme are the perfect combination.

How to slice an onion

A lot of home cooks are unsure about how to properly slice an onion. As someone who has worked in kitchens and restaurants my entire life, improperly sliced onions are a pet peeve of mine.

So here’s the easiest and quickest way to slice an onion.

With the peel still on the onion, slice it in half from root to stem. This makes it easier to take the peel and first layer of onion off. Peel the onion and set it on your cutting board, flat side down. With the root at the top, cut off the stem at the bottom. Now make small, vertical cuts, leaving the root intact.

There’s no need to make horizontal cuts through the onion, as the onion already has horizontal layers.

Now cut off the root, leaving you with long, beautiful slices of onion.

How to caramelize onions

Caramelizing onions is a slow process, but the result is totally worth it. Jammy, slightly sweet, and full of flavor.

What makes caramelized onions different than fried onions? Fried onions are cooked quickly over high heat, whereas caramelized onions are cooked low and slow. Fried onions are crispier, and caramelized onions are sweet and jammy.

To caramelize onions, add them to a pan over medium heat with a drizzle of olive oil.

Cook for 5 minutes until translucent and slightly browned, stirring occasionally. Then allow them to cook, without stirring, until they brown on the bottom of the pan. Then add a splash of stock or water to deglaze the pan, scraping up the browned bits.

Repeat this process until dark and jammy, about 30 minutes, allowing the liquid to evaporate and the onions to stick to the pan before deglazing again.

Ingredients

Haven’t been to the store or have fussy eaters? Learn more about the ingredients and substitution ideas for this caramelized onion tart recipe. See exact ingredient amounts in the recipe card below.

• Puff pastry- We use store-bought puff pastry. It can likely be found in the frozen section of your grocery store.
• Yellow onions- Flavorful and ideal for caramelizing.
• Dried thyme- Earthy and cozy, pairs perfectly with caramelized onions.
• Garlic- Adds depth.
• Salt and pepper to taste.
• Stock or water for deglazing the pan.
• Egg for egg washing the pastry.

How to Make Onion puff Pastry Tart

Cook the onions until slightly browned. Allow the onions to cook without stirring for 5 minutes, then add a splash of stock, scraping up the browned bits. Repeat this process until the onions are dark and caramelized, about 30 minutes.

Trace a 1/2 inch border onto the puff pastry and dock the center with a fork. Brush it with an egg wash and bake for 12 minutes until flaky and lightly golden. The pastry will puff up quite a bit, but the weight of the filling will flatten it a bit.

Spread the caramelized onions onto the puff pastry, leaving the 1/2 inch border around the edge. Add shredded Gouda cheese.

Return to the oven for 10 more minutes, until the cheese is melty. Slice the tart into

Erika’s Recipe Tips

• Use a butter knife to trace a border onto the pastry, and a fork to dock the center.
• Use the egg wash for golden brown pastry. If you don’t have an egg, use cream or milk.
• If using fresh thyme, use double the amount called for in the recipe card.
• If not using Gouda, use another flavorful cheese like goat cheese or Gruyere cheese.

Serving Suggestions

Slice the tart into 12 pieces and serve hot. Add a sprinkle of dried parsley for some color.

How to Store Leftover Onion Tart

Store the leftover onion tart covered in the fridge for up to 3-4 days. To reheat, bake at 350°F/180°C until heated through.

FAQ

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