Vegan Sourdough Discard Beet and Cacao Brownies
Fudgy, moist brownies built on sourdough discard and roasted beets, enriched with cacao powder and coconut oil. The beets create a tender crumb and subtle earthiness that deepens the chocolate flavor, while the sourdough adds complexity and a slight tangy note. Naturally vegan and a smart way to use your sourdough starter overflow.
- Prep
- 15 min
- Cook
- 28 min
- Wait
- 20 min
- Total
- 1 hr 3 min
- Makes
- 12 brownies (one 8×8-inch / 20×20 cm pan)
Steps
Before you start
- Preheat oven to 350°F (175°C)
- Line an 8×8-inch (20×20 cm) baking pan with parchment paper, leaving a 1-inch overhang on two sides for easy removal
- Have your sourdough discard at room temperature
- If using raw beets, roast them ahead and let cool completely before blending
Blend beet mixture
- Add roasted beets and sourdough discard to a blender or food processor.
- Blend on high speed for 60–90 seconds until completely smooth with no visible beet pieces.
- Set aside in a medium bowl.
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Ready when: Mixture is deep purple-brown and completely smooth
Tip: A food processor works well here; if using a blender, work in batches if needed. Do not overfill the blender.
Combine wet ingredients
- Pour melted coconut oil into the beet mixture and whisk together for 30 seconds until fully combined.
- Add cane sugar and vanilla extract, whisking until the sugar is mostly dissolved and the mixture is smooth and glossy.
- The mixture should look like thick chocolate pudding.
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Ready when: Mixture is smooth, glossy, and uniform in color
Tip: Don't overmix at this stage; gentle whisking prevents aerating the batter and keeps brownies dense and fudgy.
Whisk dry ingredients
- In a separate medium bowl, whisk together all-purpose flour, cacao powder, baking powder, baking soda, and sea salt.
- If using espresso powder, add it now and whisk to distribute evenly.
- This breaks up any lumps and ensures the leavening agents are evenly distributed.
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Ready when: Dry mixture is uniform in color with no visible streaks of cacao or flour
Tip: Sift the cacao powder if it's clumpy; lumps in the batter create uneven texture.
Fold in dry ingredients
- Pour the dry mixture into the wet beet mixture.
- Using a rubber spatula, fold gently 8–10 times until just combined.
- Stop when you see no more white streaks of flour.
- Do not overmix; a few lumps are fine and help preserve the fudgy texture.
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Ready when: Batter is uniform in color with no visible flour streaks; some small lumps remain
Tip: Overmixing develops gluten and can make brownies cake-like instead of fudgy. Fold, don't stir.
Add chocolate chips
- If using vegan dark chocolate chips, gently fold them into the batter with 2–3 folds of the spatula.
- Reserve about 2 tablespoons to sprinkle on top before baking.
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Ready when: Chocolate chips are evenly distributed with no clumps visible
Transfer to pan and smooth
- Pour batter into the prepared 8×8-inch (20×20 cm) baking pan.
- Spread gently with a rubber spatula until level.
- Sprinkle reserved chocolate chips (if using) over the top and lightly press them in with the spatula.
- The batter should be about ¾ inch (2 cm) thick.
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Ready when: Surface is level and smooth
Tip: Don't overwork the batter at this stage. A gentle hand keeps the brownies tender.
Bake until setOven 350°F / 175°C
- Place pan in preheated 350°F (175°C) oven and bake for 24–28 minutes.
- The brownies are done when a toothpick inserted into the center comes out with 1–2 moist crumbs (not wet batter).
- The top should look set and slightly matte, and the edges should just begin to pull away from the sides of the pan.
- Do not overbake or the brownies will be dry.
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Ready when: Toothpick inserted in center comes out with 1–2 moist crumbs; top is set and matte; edges pull slightly from pan sides
Tip: Start checking at 24 minutes. Residual heat continues cooking after removal. Slightly underbaked is better than overbaked for fudgy brownies.
Cool in pan
- Remove brownies from oven and set pan on a wire rack or cool surface.
- Let cool in the pan for 20 minutes.
- During this time, the brownies will continue to set as they cool.
- Do not cut or move them while still very hot or they will crumble.
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Ready when: Pan is cool enough to touch comfortably; brownies are firm but still warm
Tip: Cooling in the pan is essential—it allows the structure to set so the brownies don't fall apart when removed.
Remove and cut
- Using the parchment overhang, carefully lift the entire brownie block out of the pan onto a cutting board.
- Let cool for another 5–10 minutes until completely cool to the touch.
- Using a sharp, dry knife, cut into 12 equal squares (3 rows × 4 columns, or 2 rows × 6 columns—adjust to your preference).
- Wipe the knife with a damp cloth between cuts for clean edges.
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Ready when: Brownies are cool to the touch and can be cut cleanly without crumbling
Tip: A warm knife or a sharp serrated knife dipped in hot water between cuts reduces crumbling and gives you neat, professional-looking brownies.
Good to know
Tips
- Sourdough discard doesn't need to be bubbly or active; you can use unfed discard right from the fridge. The beets mask any sour flavor, though a slightly tangy note is desirable.
- The beets are key to keeping these brownies moist and tender. They add moisture without eggs, so don't skip them or substitute with just more sourdough.
- For a deeper chocolate flavor, add ½ teaspoon espresso powder to the dry ingredients. It amplifies cacao without adding coffee taste.
- If you prefer fudgier brownies, reduce baking time by 1–2 minutes and accept a touch of wet batter on the toothpick. If you like cake-like brownies, bake an extra 2 minutes until the toothpick comes out nearly clean.
Make ahead
Bake the brownies up to 2 days ahead. Store in an airtight container at room temperature. You can also freeze the batter in a lined pan, wrap tightly in plastic wrap and foil, and bake directly from frozen, adding 2–3 minutes to the baking time. Unbaked batter keeps refrigerated for up to 24 hours.
Storage & reheating
Room temperature (2–3 days): Store in an airtight container, layer with parchment if needed. Refrigerator (up to 1 week): Cover tightly to prevent drying out. Freezer (up to 3 months): Wrap individual brownies in plastic wrap, then place in a freezer-safe container. Thaw at room temperature for 30 minutes before serving. Reheat gently in a 300°F (150°C) oven for 5 minutes if you prefer them warm.
Substitutions
- roasted beetroot, cooled → 1 cup (240 g) canned beetroot, drained and blended smooth, or 1 cup (240 ml) fresh beet juice reduced by half over medium heat until it measures ¾ cup. Canned beets work well and save time. If using beet juice, reduce it first to concentrate the flavor and avoid overly wet batter. Fresh beetroot should be roasted and cooled first for best results.
- unsweetened cacao powder (Dutch or natural) → ½ cup (50 g) unsweetened cocoa powder (non-Dutch) or a mix of ¼ cup (25 g) cacao powder + ¼ cup (20 g) natural unsweetened cocoa powder. Dutch-process cacao is neutral; natural cocoa is more acidic and may enhance the sourdough tang. Both work; adjust to taste preference.
- coconut oil, refined or unrefined → ½ cup (120 ml) vegan butter, melted, or ⅓ cup (80 ml) neutral oil such as avocado or sunflower oil. Vegan butter adds richness; neutral oils create a lighter crumb. Coconut oil provides the most flavor and moisture.
- organic cane sugar → ¾ cup (150 g) coconut sugar or ⅔ cup (135 g) maple syrup (reduce other wet ingredients slightly if using liquid sweetener). Coconut sugar has a slight caramel note that complements the beets well. Maple syrup will make the batter wetter; reduce sourdough by 2 tablespoons if using.