30-Minute Sourdough Discard Pesto Parmesan Biscotti
Crispy, twice-baked Italian biscotti made with sourdough discard, fresh basil pesto, and sharp Parmesan. These savory biscotti are ready in just 30 minutes and make an ideal accompaniment to soup, salad, or cheese boards. The sourdough discard adds subtle tang while the pesto and Parmesan deliver bright, umami-rich flavor throughout.
- Prep
- 10 min
- Cook
- 18 min
- Wait
- 2 min
- Total
- 30 min
- Makes
- 24 biscotti pieces
Steps
Before you start
- Preheat oven to 400°F (200°C) and line a large baking sheet with parchment paper.
- Have sourdough discard at room temperature (not cold from the fridge).
- Grate Parmesan fresh if possible for better texture and flavor.
Mix dough
- In a medium bowl, whisk together sourdough discard, all-purpose flour, pesto, egg, grated Parmesan, salt, and black pepper until a stiff, shaggy dough forms.
- Mix just until no dry flour remains—don't overmix.
- The dough will be denser than typical bread dough.
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Ready when: no dry flour visible; dough is combined
Tip: Don't overmix—lumpy dough leads to crispier, more rustic biscotti.
Shape into logs
- Turn dough onto a lightly floured surface and divide in half.
- Roll or press each half into a log about 8 inches (20 cm) long, 2 inches (5 cm) wide, and ¾ inch (2 cm) tall.
- Place both logs on the prepared baking sheet, leaving 2 inches (5 cm) between them.
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Ready when: logs are evenly shaped and spaced
Tip: Even, consistent logs ensure uniform baking and slicing. Slightly flatten the tops for a flatter first bake.
Brush and first bakeOven 400°F / 205°C
- Brush each log lightly with egg wash.
- Bake at 400°F (200°C) for 12–14 minutes until the logs are golden brown and firm to the touch.
- They should feel slightly hard on the outside but still give a little when pressed.
- Remove from oven and let cool for 2 minutes on the baking sheet.
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Ready when: logs are golden brown and firm; spring back slightly when pressed
Tip: Don't let them over-bake in the first round—they'll dry out more during the second bake.
Cool and slice
- Let the logs cool for 2 minutes until they're just cool enough to handle safely.
- Using a sharp serrated bread knife, cut each log on a slight diagonal into ½-inch (1.25 cm) thick slices.
- You'll get about 12 pieces from each log.
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Ready when: slices are clean, with no crumbling
Tip: Use a serrated knife and a gentle sawing motion—a dull knife will crumble the warm biscotti. If too warm, wait another minute.
Second bakeOven 400°F / 205°C
- Arrange the sliced biscotti upright (standing on one cut side) on the baking sheet, cut side down.
- Bake at 400°F (200°C) for 4–6 minutes until the cut sides are deep golden and crispy.
- If desired, flip them over and bake another 2–3 minutes for extra crispness on both sides.
- Watch carefully—they can go from golden to dark quickly.
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Ready when: biscotti are deep golden brown on both cut sides; sound hollow when tapped
Tip: For extra-crispy biscotti, flip them halfway through. If they're still soft after cooling, they need another minute or two in the oven.
Cool completely
- Transfer biscotti to a cooling rack and let them cool completely, about 10 minutes.
- They'll firm up and become even crispier as they cool.
- Once fully cool, they're ready to serve or store.
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Ready when: biscotti are completely cool and hard throughout
Tip: Cooling on a rack allows air to circulate underneath, preventing moisture from softening the bottoms.
Good to know
Tips
- Sourdough discard quality matters: it should be bubbly and smell pleasantly sour, not gray or separated. Discard from a healthy starter gives the best flavor and rise.
- Make fresh pesto in minutes by pulsing fresh basil, garlic, pine nuts (or walnuts), grated Parmesan, and olive oil in a food processor—or use store-bought if pressed for time.
- These biscotti are ideal for dunking in warm minestrone or tomato soup, or serving alongside a cheese board or antipasto platter.
- For a spicier version, add ¼ teaspoon of red pepper flakes to the dough in step 1.
Storage & reheating
Store cooled biscotti in an airtight container at room temperature for up to 1 week. They can also be frozen in a freezer bag for up to 3 months; thaw at room temperature before serving. For extra crispness, reheat on a baking sheet at 300°F (150°C) for 3–5 minutes before serving.
Substitutions
- fresh basil pesto → sun-dried tomato paste or tapenade. Use the same amount (⅓ cup/80 ml) for a different Mediterranean flavor profile. Sun-dried tomato will add a slightly sweeter, earthier note.
- Parmigiano-Reggiano, finely grated → Pecorino Romano or aged Asiago. Both offer sharp, salty flavors similar to Parmesan. Use the same amount. Pecorino will be slightly more peppery.
- all-purpose flour → whole wheat pastry flour or spelt flour. Use the same weight (155 g) for a slightly nutty flavor. The dough may be slightly denser but will bake similarly.
- sourdough starter discard, room temperature → active sourdough starter (bubbly, just fed) or Greek yogurt at room temperature. Use the same amount (1 cup/240 ml). Active starter will add more tang; yogurt will make them slightly softer. If using active starter, reduce salt by ¼ tsp.
