Caramelized Onion Sourdough Bread with Asiago

This caramelized onion sourdough bread with Asiago has a crisp, deeply browned crust and a tender crumb dotted with sweet onions and nutty cheese. The dough takes time because sourdough needs a long fermentation, but the hands-on work is simple: mix, stretch, fold, shape, and bake. The finished loaf is excellent with soup, eggs, sandwiches, or a little butter while it is still warm.

Why You’ll Love This Caramelized Onion Sourdough

• Big savory flavor: Slow-cooked onions become sweet and jammy, balancing the tangy dough.
• Beautiful texture: Steam and high heat create a crisp crust while the interior stays chewy and soft.
• Make-ahead schedule: An overnight refrigerator proof makes the bake easier to plan.
• Versatile loaf: Serve it with soup, use it for panini, or toast it for breakfast.
• Worth the project: A small amount of Asiago gives the bread an aromatic, savory finish.

Ingredients

For the dough

• 100 grams active sourdough starter, 100% hydration
• 350 grams warm water
• 500 grams bread flour
• 10 grams fine sea salt
• 1 tablespoon olive oil, optional

For the filling

• 2 large yellow onions, thinly sliced
• 1 tablespoon olive oil
• 1 tablespoon unsalted butter
• 1/2 teaspoon kosher salt
• 1 teaspoon brown sugar, optional
• 1 teaspoon fresh thyme leaves
• 1 cup shredded Asiago cheese

Before You Start

Your starter should be active, bubbly, and recently fed. A small spoonful dropped into water does not always provide a perfect test, so look for a starter that has doubled in volume and smells pleasantly tangy. The exact fermentation time depends on room temperature. The dough will move faster in a warm kitchen and slower in a cool one.

How to Make Caramelized Onion Sourdough Bread

1. Caramelize the onions. Heat the olive oil and butter in a wide skillet over medium-low heat. Add the onions and salt. Cook for 30 to 40 minutes, stirring every few minutes, until deeply golden and jammy.
2. Finish and cool the onions. Stir in the brown sugar and thyme during the final 5 minutes if using. Spread the onions on a plate and cool completely. Warm onions can weaken the dough and slow fermentation.
3. Mix the dough. Combine the starter and warm water in a large bowl. Add the bread flour and mix until no dry flour remains. Cover and rest for 30 minutes.
4. Add salt. Sprinkle in the salt and optional olive oil. Pinch and fold the dough until the salt is evenly distributed. Cover and rest for another 30 minutes.
5. <strongStretch and fold. Over the next 2 hours, complete four sets of stretch-and-folds, one every 30 minutes. Lift one side of the dough, stretch it upward, and fold it over the center. Turn the bowl and repeat three more times.
6. Add the filling. During the second or third fold, add the cooled onions and Asiago. Fold gently so the cheese and onions spread through the dough without tearing it.
7. Bulk ferment. Cover the bowl and let the dough rise until it looks puffy and has increased by about 50 percent. This may take 3 to 5 hours from the start of mixing, depending on room temperature.
8. Shape the loaf. Turn the dough onto a lightly floured surface. Shape it into a tight round by pulling the edges toward the center, then flipping it seam-side down and gently tightening the surface.
9. Proof overnight. Place the dough seam-side up in a floured banneton or towel-lined bowl. Cover and refrigerate for 8 to 14 hours.
10. Heat the oven. Place a Dutch oven inside the oven and preheat to 500°F for at least 45 minutes.
11. Score the dough. Turn the cold dough onto parchment. Use a sharp lame or knife to cut one deep slash across the top.
12. Bake with steam. Lower the dough into the hot Dutch oven, cover, and bake at 475°F for 20 minutes. Remove the lid and bake another 20 to 25 minutes at 450°F, until deeply browned.
13. Cool before slicing. Transfer the bread to a rack and cool for at least 1 hour. Cutting too early can make the crumb gummy.

Tips and Variations

• Cool the onions fully: Warm filling can make the dough sticky and interfere with fermentation.
• Use another cheese: Gruyère, sharp cheddar, fontina, or Parmesan can replace Asiago.
• Add herbs: Rosemary, sage, chives, or parsley pair beautifully with caramelized onions.
• Watch the salt: Asiago is salty, so do not increase the dough salt without tasting your cheese.
• Make two small loaves: Divide the dough after bulk fermentation and bake in two smaller Dutch ovens, reducing the bake time.
• Use a baking stone: If you do not have a Dutch oven, bake on a preheated stone with a pan of boiling water for steam.
• Prevent burning: If the cheese on the surface darkens quickly, lower the oven temperature by 25°F during the uncovered stage.
• Add garlic: Stir a roasted garlic clove or two into the cooled onions for a deeper savory flavor.

For another naturally fermented bake, try this sourdough rosemary focaccia. The loaf is excellent in an Italian chicken panini or beside a simple garden vegetable frittata.

Storage and Reheating

Store the cooled loaf in a paper bag or bread box for up to 2 days. Avoid sealing it in plastic while the crust is crisp because trapped moisture will soften it. For longer storage, slice and freeze the bread in an airtight bag for up to 2 months. Toast slices directly from frozen.

To refresh a whole loaf, mist the crust lightly with water and warm it in a 350°F oven for 8 to 10 minutes. Because the bread contains Asiago and butter, the FDA’s food-allergy guidance is useful when serving guests with dairy allergies.

Frequently Asked Questions

How do I make caramelized onion sourdough bread with Asiago?

Caramelize onions until jammy, mix a sourdough dough, add the cooled onions and cheese during stretch-and-folds, ferment until puffy, proof overnight, and bake in a hot Dutch oven.

Why is my sourdough loaf dense?

The starter may have been weak, the dough may have under-fermented, or the dough may have lost too much gas during shaping. Use an active starter and wait for a puffy dough before shaping.

Can I skip the overnight proof?

You can proof at room temperature for 1 to 2 hours after shaping, but the overnight refrigerator proof develops more flavor and makes the dough easier to score.

How do I keep onions from making the dough wet?

Cook the onions until nearly all moisture has evaporated and cool them completely. Spread them on a plate rather than leaving them in a warm skillet.

What can I serve with this sourdough?

Serve it with soup, eggs, roasted vegetables, charcuterie, grilled meats, or a simple salad. Toasted slices are excellent with butter and a little flaky salt.

Serving Ideas

Let the loaf cool completely, then cut it into thick slices so the onion and cheese remain visible. Toast a slice and top it with a fried egg, or use two slices for a grilled cheese sandwich. The savory crumb also makes excellent croutons for soup and salad. If you are serving it with dinner, warm individual slices for a few minutes just before bringing them to the table.

Its savory flavor makes everyday meals feel special.