Caramelized Onion and Gorgonzola Crostini

Name: Caramelized Onion and Gorgonzola Crostini
Prep time: 10 min
Cook time: 30 min
Total time: 40 min
Yield: 12 pieces
Ingredients: 1 baguette, sliced into 1/2 inch pieces; 2 tablespoons olive oil; 2 large onions, thinly sliced; 1 tablespoon butter; 1 teaspoon balsamic vinegar; 1/2 cup Gorgonzola cheese, crumbled; Fresh thyme leaves, for garnish (optional)

Highlighted under: Sugar & Spice Desserts

I absolutely love serving these caramelized onion and Gorgonzola crostini at gatherings. They bring a delightful combination of sweet and savory flavors that truly impress my guests. The crispy crostini provide the perfect base, while the rich, creamy cheese melts beautifully on top. With just a handful of ingredients and a little patience, I can create a sophisticated appetizer that's bound to be a hit. Whether it’s a cozy get-together or a fancy soirée, these crostini always elevate the occasion.

Created by

Lina

Last updated on 2026-01-17T14:14:27.840Z

When I first tried caramelized onions, I was amazed by their depth of flavor. Taking the time to slowly cook them unlocks their natural sweetness, making them perfect for pairing with tangy Gorgonzola cheese. I discovered that the trick to achieving that beautiful caramel color is to be patient and stir occasionally, allowing the onions to brown without burning. This method transforms the humble onion into something truly magical.

As I serve these crostini, the reactions from everyone are priceless. The creaminess of the Gorgonzola balances the sweetness of the onions brilliantly. I also love that I can prepare the onions in advance, making assembly quick when guests arrive. It’s an appetizer that’s not only simple but also feels gourmet!

        Why You'll Love This Recipe
        Sweet caramelized onions that enhance every bite
Creamy Gorgonzola that perfectly complements the crunchy base
Impressive yet easy to make for any occasion

      

Perfecting the Caramelization Process

Caramelizing onions is a delicate process that significantly enhances their natural sweetness. Start by slicing the onions uniformly to ensure they cook evenly. The key is to cook them on medium heat, stirring occasionally to prevent burning, for about 20-25 minutes. You'll know they're ready when they turn a deep golden brown and have a silky texture. If you find they are browning too quickly or sticking, reduce the heat slightly and add a small splash of water to deglaze the pan.

Balsamic vinegar adds depth and acidity, balancing the sweetness from the onions. Stir it in towards the end of the cooking time to avoid burning the vinegar’s sugars. This enhances the overall flavor profile and adds a hint of tang that complements the Gorgonzola beautifully. Be sure to taste and adjust the vinegar as needed; every batch of onions can carry a different level of sweetness.

Tips for the Perfect Crostini

For the crostini, the choice of baguette is crucial. I recommend opting for a day-old baguette, as it will dry out slightly, providing better crunch when baked. Slice the baguette into 1/2 inch thick pieces to achieve the ideal bite-sized base that holds up well under the toppings. Brush each side with olive oil to promote even browning and prevent them from becoming too dry during baking.

It's important to keep an eye on your crostini as they bake. After about 8 minutes, check for golden edges, as oven temperatures can vary. You want them crispy but not burnt. If you're preparing for a larger gathering, consider doubling the recipe; make sure to bake them in batches to avoid overcrowding the baking sheet, which can lead to uneven cooking.

Ingredients

To create these delicious crostini, gather the following ingredients:

Ingredients

1 baguette, sliced into 1/2 inch pieces
2 tablespoons olive oil
2 large onions, thinly sliced
1 tablespoon butter
1 teaspoon balsamic vinegar
1/2 cup Gorgonzola cheese, crumbled
Fresh thyme leaves, for garnish (optional)

With these ingredients on hand, you're ready to create a delicious appetizer!

Instructions

Follow these simple steps to prepare your crostini:

Prepare the Crostini

Preheat your oven to 400°F (200°C). Arrange the baguette slices on a baking sheet and brush each side with olive oil. Bake for about 10 minutes or until they are golden and crispy.

Remove from the oven and set aside.

Caramelize the Onions

In a large skillet, melt the butter and add the olive oil over medium heat. Add the sliced onions and cook slowly, stirring occasionally for about 20-25 minutes until they are deep golden brown and caramelized. Stir in the balsamic vinegar and cook for an additional 2 minutes.

Assemble the Crostini

Spoon a generous amount of the caramelized onions onto each crostini. Top with crumbled Gorgonzola cheese, then return to the oven for 5 minutes until the cheese is slightly melted.

Garnish and Serve

Remove from the oven, garnish with fresh thyme if desired, and serve warm. Enjoy your delicious appetizer!

These steps will guide you to making the perfect crostini!

Pro Tips

For added depth of flavor, consider adding a splash of white wine or a pinch of sugar to the onions while caramelizing. This can enhance the sweetness and complexity of the dish.

Serving Suggestions

These crostini can be served warm but can also hold up well at room temperature, making them perfect for parties. Try pairing them with a light salad or a charcuterie board to add a variety of flavors and textures. A simple arugula salad with a lemon vinaigrette can offer a refreshing contrast to the rich cheese and sweet onions.

For a twist, consider adding a layer of fig jam beneath the caramelized onions for an extra layer of sweetness. The fig and Gorgonzola combination is a classic that never disappoints. You can also experiment with different cheeses like goat cheese or feta if Gorgonzola isn’t available or if you're looking for a different flavor profile.

Make-Ahead and Storage Tips

You can prepare the caramelized onions in advance and store them in an airtight container in the fridge for up to four days. When you’re ready to serve, reheat them gently in a pan over low heat to bring back their glossy texture. This not only saves time on the day of your event but allows the flavors to meld even more as they sit.

If you make a large batch of crostini, be cautious about storing them. Ideally, they are best served fresh but can also be kept in an airtight container for up to a day. Re-crisp them in the oven for a few minutes before serving. However, if you notice any moisture, it's best to eat them fresh, as that will maintain their ideal crunch.

Questions About Recipes

→ Can I prepare the onions in advance?

Absolutely! You can caramelize the onions up to two days ahead. Just store them in an airtight container in the refrigerator and reheat before serving.

→ What can I substitute for Gorgonzola cheese?

If you're not a fan of Gorgonzola, feta cheese or brie can also work well as alternatives.

→ How do I store leftovers?

Store any leftover crostini in an airtight container in the fridge, though they are best enjoyed fresh. You can reheat them in the oven to revive some crispness.

→ Can I make these crostini gluten-free?

Yes! Use gluten-free baguette or any gluten-free bread of your choice to make this recipe suitable for a gluten-free diet.