This Porcini & Caramelized Red Onion Sourdough Focaccia is rich, savory, and loaded with depth. The earthiness of porcini mushrooms pairs perfectly with the sweetness of slowly caramelized red onions. The sourdough base gives it chew and tang, while the toppings take it over the top.
Whether it's your first focaccia or your fiftieth, this version is approachable, naturally vegan (or optionally cheesy), and completely crowd-pleasing.
Why You'll Love This Recipe
- Deep umami from mushrooms and sweet-savory contrast from red onions
- Chewy crumb with crisp, golden edges
- Naturally vegan with optional cheese boost
- Great make-ahead option with overnight proof
- Versatile for sandwiches, sides, or snacking
- No shaping, scoring, or special tools required
Tools Needed
- Mixing bowl or stand mixer
- Dough hook attachment (optional but helpful)
- Kitchen scale
- 9×13” baking pan (non-stick recommended)
- Small sauté pan (for mushrooms)
- Fine mesh strainer (for soaking liquid)
Ingredients Needed
Dough
- 500g bread flour
- 10g salt
- 350g warm water (around 85°F)
- 120g active sourdough starter (or levain*)
- 30g extra virgin olive oil (plus more for the pan and topping)
*Levain: Mix 40g starter + 40g bread flour + 40g water. Let rise 4–5 hours.
Toppings
- 15g dried porcini mushrooms
- ½ cup boiling water (for rehydration)
- 1 tablespoon olive oil (for sautéing mushrooms)
- 1 garlic clove, minced
- 1 teaspoon fresh thyme or rosemary leaves
- 1 medium red onion, thinly sliced
- 1 tablespoon olive oil (for onions)
- Pinch of chili flakes (optional)
- Flaky salt, to finish
- Optional: grated parmesan or pecorino
Step by Step Instructions
1. Prep the Toppings
Rehydrate Porcini:
- Soak dried porcini in ½ cup boiling water for 20–30 minutes.
- Strain (reserve the liquid), chop mushrooms roughly.
Sauté Porcini:
- Heat 1 tablespoon olive oil in a skillet. Add chopped porcini, garlic, and thyme.
- Sauté 2–3 minutes until fragrant. Set aside.
Caramelize Onion:
- In the same skillet, add 1 tablespoon olive oil and the thinly sliced red onion.
- Cook over medium-low heat for 20–25 minutes, stirring occasionally, until soft, sweet, and jammy. Deglaze with a splash of the mushroom soaking liquid if needed.
2. Mix the Dough
In a bowl or stand mixer, combine:
- 500g bread flour
- 10g salt
- 350g warm water
- 120g starter (or levain)
Mix until combined. Dough will be sticky.
Add 30g olive oil and knead until smooth, elastic, and pulling from the bowl (10–15 minutes in mixer or up to 20 by hand).
3. Bulk Fermentation
Transfer to a lightly oiled bowl. Ferment 5–6 hours at 75–78°F.
Do 4 sets of stretch-and-folds during the first 2 hours, every 30 minutes.
Dough is ready when nearly doubled, bubbly, and elastic.
4. Cold Overnight Proof (Optional)
Cover and refrigerate overnight or up to 48 hours. Skip if baking same-day.
5. Final Proof
Grease a 9×13” baking pan generously. Gently transfer dough into the pan.
Let proof at 75–78°F for 4 hours, stretching gently every 30 minutes to help it fill the pan. It should double and jiggle like jello.
6. Top & Bake
Preheat oven to 450ºF (232ºC).
Right before baking:
- Dimple dough with oiled fingertips
- Evenly distribute caramelized onions and sautéed porcini
- Press them slightly into the dough
- Top with chili flakes (if using), flaky salt, and another drizzle of olive oil
Optional: Add grated parmesan or pecorino during the last 5 minutes of baking.
Bake on lower rack 20 minutes, then top rack 5 minutes, until golden brown and crisp.
7. Cool & Serve
Cool in the pan 10–15 minutes, then transfer to a wire rack. Let rest at least 1 hour before slicing.
Storage & Reheating
- Store wrapped in foil or beeswax at room temp for 1–2 days
- To refresh, bake at 350ºF for 5–10 minutes
- Freeze wrapped slices up to 3 months
- Best served warm, dipped in olive oil or alongside soup or salad
Topping Variations to Try
- Porcini with caramelized onions and rosemary
- Porcini with garlic and lemon zest
- Porcini with chili flakes and pecorino
- Porcini with black olives and oregano
Porcini & Caramelized Red Onion Sourdough Focaccia
Ingredients
- 500 g bread flour
- 10 g salt
- 350 g warm water
- 120 g active sourdough starter
- 30 g olive oil
- 15 g dried porcini mushrooms
- 1/2 cup boiling water for soaking porcini
- 1 tbsp olive oil for sautéing mushrooms
- 1 clove garlic minced
- 1 tsp fresh thyme
- 1 red onion thinly sliced
- 1 tbsp olive oil for caramelizing onions
- chili flakes optional
- flaky salt
- grated parmesan optional
Equipment
Method
- Soak porcini mushrooms in boiling water for 20–30 minutes. Strain and chop. Sauté porcini with garlic and thyme. Separately caramelize sliced onions in olive oil until soft and jammy.
- Combine flour, salt, water, and starter. Mix until sticky. Add olive oil and knead until smooth and elastic.
- Let the dough rise 5–6 hours, performing four stretch-and-folds during the first 2 hours.
- Cover and refrigerate overnight or up to 48 hours.
- Transfer dough to an oiled 9×13 pan and let rise 4 hours until bubbly and jiggly.
- Dimple dough, top with porcini and caramelized onions, add flaky salt and olive oil. Bake at 450°F for 20 minutes on the lower rack, then 5 minutes on the top rack.
- Cool 10–15 minutes in the pan, then cool 1 hour before slicing.
Nutrition
Notes
Topping Variations to Try
- Porcini with caramelized onions and rosemary
- Porcini with garlic and lemon zest
- Porcini with chili flakes and pecorino
- Porcini with black olives and oregano
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One response to “Porcini Mushroom and Caramelized Onion Sourdough Focaccia”
I loved this.
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