Caramelized Onion and Gorgonzola Crostini

Name: Caramelized Onion and Gorgonzola Crostini
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Yield: 8 servings
Ingredients: 1 French baguette, sliced into 1/2 inch slices; Olive oil, for brushing; Salt and pepper, to taste; 2 large onions, thinly sliced; 2 tablespoons butter; 1 tablespoon olive oil; 1/2 cup gorgonzola cheese, crumbled; Fresh thyme, for garnish

Highlighted under: Sweet Indulgence Recipes

I absolutely love serving these caramelized onion and gorgonzola crostini as an appetizer at gatherings. The sweet, rich flavor of the caramelized onions combined with the tangy gorgonzola makes for an irresistible bite. Each toast is a delightful balance of textures and flavors, making them perfect for any occasion. Whether it's a casual get-together or a fancy dinner party, these crostini always impress. Plus, they are incredibly easy to prepare and can be made ahead of time, allowing me to enjoy the company of my guests.

Created by

Emma

Last updated on 2026-01-17T15:18:27.867Z

As I set out to create the perfect appetizer, I realized I wanted something that combined sweet and savory elements. After several attempts, my caramelized onion and gorgonzola crostini hit the mark perfectly. The slow-cooked onions become rich and sweet, while the gorgonzola adds a creamy, tangy contrast that pairs beautifully with a crunchy crostini. I've found that letting the onions caramelize slowly is key to developing their flavor.

Making these crostini has become a staple in my recipe repertoire. Whenever I have friends over, they rave about the delicious combination. It's a simple yet impressive dish that showcases the beauty of well-prepared ingredients. I love sprinkling fresh herbs on top for an added burst of flavor and color!

        Why You'll Love This Recipe
        Sweet and savory flavor harmony with caramelized onions and gorgonzola.
Crispy crostini providing a satisfying crunch.
Quick preparation ensures you can spend more time with your guests.

      

Mastering Caramelization

Caramelizing onions is a technique that transforms their natural sugars into rich, golden sweetness. It’s essential to keep the heat at medium to ensure even cooking without burning. Stir the onions every few minutes, allowing them to develop a deep flavor and a jam-like texture. If you notice they’re browning too quickly, reduce the heat slightly and add a splash of water to deglaze the pan. This will help to lift those flavorful brown bits and incorporate them back into the onions.

Using both butter and olive oil for caramelizing not only enhances flavor but also raises the smoke point, making it easier to achieve the perfect golden color. Choose sweet yellow onions for a balanced flavor, but if you're looking for something sharper, red onions or sweet Vidalias can also work beautifully. Just be prepared for a slightly different taste profile that can add depth to your crostini.

Crostini Perfection

Achieving a crispy crostini is key to balancing the soft, luscious toppings. When preparing the baguette, ensure that the slices are uniform—about 1/2 inch thick—to guarantee even toasting. Layer the slices on a baking sheet without overcrowding; this will allow for proper airflow and browning. Brush the oil generously, but avoid soaking the bread, which can lead to a soggy texture. You'll know they are ready when they are golden with slightly firm edges, typically around 5-7 minutes in the oven.

If you're looking to add an extra layer of flavor to your crostini, consider rubbing the toasted slices with a garlic clove just after they come out of the oven. This simple addition can impart a subtle, aromatic touch that beautifully complements the savory toppings while adding a rustic twist to your presentation.

Ingredients

For the Crostini

1 French baguette, sliced into 1/2 inch slices
Olive oil, for brushing
Salt and pepper, to taste

For the Topping

2 large onions, thinly sliced
2 tablespoons butter
1 tablespoon olive oil
1/2 cup gorgonzola cheese, crumbled
Fresh thyme, for garnish

Instructions

Prepare the Onions

In a large skillet, melt the butter and olive oil over medium heat. Add the sliced onions and a pinch of salt. Cook, stirring occasionally, for about 25-30 minutes until the onions are caramelized and golden brown.

Toast the Baguette

While the onions are cooking, preheat your oven to 400°F (200°C). Arrange the baguette slices on a baking sheet and brush one side lightly with olive oil. Season with salt and pepper. Toast in the oven for about 5-7 minutes until golden and crispy.

Assemble the Crostini

Once the onions are caramelized and the baguette slices are toasted, top each slice of baguette with a generous spoonful of caramelized onions. Sprinkle with crumbled gorgonzola cheese.

Finish and Serve

Return the assembled crostini to the oven for an additional 5 minutes or until the cheese is slightly melted. Garnish with fresh thyme and serve warm.

Pro Tips

For extra flavor, consider adding a drizzle of balsamic reduction atop the crostini before serving.

Make-Ahead Tips

These caramelized onion and gorgonzola crostini can be prepped in advance, making them perfect for entertaining. You can caramelize the onions a day ahead and store them in an airtight container in the refrigerator. When you're ready to serve, simply reheat the onions gently in a skillet over low heat until warmed through. The flavors will deepen overnight, providing an even richer topping for your crostini.

As for the baguette, you can toast the slices ahead of time as well. Allow them to cool completely before storing them in an airtight container at room temperature. Just remember that they should be assembled and baked right before serving to ensure those textures are just right: crispy on the outside and gooey on top.

Serving Variations

While this recipe shines as is, consider adding your favorite toppings for variety. Chopped walnuts or pecans can bring a delightful crunch, while a drizzle of balsamic reduction adds a tangy finish. For an herbaceous note, try mixing in some chopped fresh parsley or basil with the thyme garnish, which will brighten the overall flavor and presentation.

If you're hosting a cheese lovers’ night, extend the crostini theme with additional toppings. Try combining different cheeses such as goat cheese or feta with the gorgonzola, or alternate layers of ingredients like roasted red peppers or fig spread for a gourmet touch that showcases your creativity.

Questions About Recipes

→ Can I make the caramelized onions ahead of time?

Absolutely! You can prepare the onions a day in advance and store them in an airtight container in the refrigerator. Just reheat before assembling the crostini.

→ What can I substitute for gorgonzola?

If you prefer a milder cheese, you can use goat cheese or feta as a substitute.

→ How long can I keep leftover crostini?

The crostini are best enjoyed fresh, but you can store leftovers in the fridge for up to 2 days. Reheat them in the oven to regain their crispiness.

→ Can I make these crostini gluten-free?

Yes! Use gluten-free bread or crackers as a base for the crostini.