Sourdough Onion Focaccia (Printable Version)

Chewy sourdough focaccia with caramelized onions and sea salt, featuring a light, airy texture.

# What You'll Need:

→ Sourdough Starter

01 - 3.5 oz active sourdough starter at 100% hydration

→ Dough

02 - 14.1 oz bread flour
03 - 10.1 fl oz lukewarm water
04 - 0.35 oz fine sea salt
05 - 0.68 fl oz extra-virgin olive oil

→ Topping

06 - 2 medium yellow onions, thinly sliced
07 - 1 tablespoon olive oil
08 - 1 teaspoon flaky sea salt
09 - 1 teaspoon fresh rosemary leaves
10 - Freshly ground black pepper to taste

# Directions:

01 - In a large bowl, combine sourdough starter, bread flour, and lukewarm water until a shaggy dough forms. Cover and rest for 30 minutes.
02 - Add fine sea salt and extra-virgin olive oil to the dough and mix thoroughly until fully incorporated.
03 - Over the next 2 hours, perform 3 to 4 sets of stretch and folds every 30 minutes to develop gluten strength.
04 - Cover the bowl and allow dough to rise at room temperature for 6 to 8 hours until volume doubles.
05 - Generously oil a 9x13-inch baking pan. Gently transfer dough to the pan without deflating, then use oiled fingers to stretch and press it to fit the pan evenly.
06 - Cover the shaped dough and refrigerate for 8 to 12 hours to develop flavor and improve texture.
07 - Heat 1 tablespoon olive oil in a skillet over medium-low heat. Add sliced onions and cook, stirring occasionally, for 20 to 25 minutes until golden, tender, and sweet. Allow to cool completely.
08 - Remove dough from refrigerator and let rest at room temperature for approximately 1 hour.
09 - Preheat oven to 425°F. Using your fingertips, create a dimpled surface across the dough. Drizzle with additional olive oil, then distribute caramelized onions, flaky sea salt, rosemary, and black pepper evenly over the top.
10 - Bake for 25 to 30 minutes until golden brown with crisp edges.
11 - Cool slightly before slicing and serving warm.

# Additional Tips::

01 -
  • The overnight fermentation does the heavy lifting for you—flavor develops while you sleep, and the dough becomes impossibly airy.
  • Caramelized onions are sweeter and more forgiving than you'd think, turning even a first attempt into something bakery-worthy.
  • One pan, minimal shaping, maximum impact—this bread delivers restaurant-quality results without the fuss.
02 -
  • Sourdough timing is flexible but temperature-dependent—a cold kitchen means slower fermentation, which is actually your friend because it gives you a wider window to shape and bake without dough overproofing.
  • Resist the urge to skip the overnight refrigeration; it's not laziness, it's strategy—cold fermentation develops flavor and makes the dough easier to handle and dimple than a warm, fragile one.
03 -
  • If your kitchen runs cold, proof the dough in a turned-off oven with the light on, or place it near (not directly on) a heating vent to maintain an ideal 24°C temperature.
  • Use an instant-read thermometer on your water—80°F to 85°F (27°C to 29°C) is the sweet spot that keeps fermentation steady without shocking the starter.
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