Apple Crumble Sourdough Cake
Soft, spiced cake with juicy apple slices and golden streusel — a sourdough twist on a classic comfort bake.
At a Glance
Loaf Style: Crumble-topped snack cake
Skill Level: Beginner to Intermediate
Total Time: ~12–18 hours (includes optional chill)
Prep Time: ~30 minutes
Yield: One 8x8” cake
Hydration: N/A
Bake Temp: 350°F / 175°C
Baking Vessel: Square baking dish lined with parchment
Ingredients
Cake Batter
100g sourdough discard (unfed starter)
180g all-purpose flour
100g granulated sugar
50g brown sugar
½ tsp salt
1 tsp baking powder
½ tsp baking soda
1 tsp ground cinnamon
2 large eggs
100g whole milk or yogurt
100g unsalted butter, melted
1 tsp vanilla extract
Apple Layer
1 large apple, thinly sliced (peeled if preferred)
1 tsp lemon juice
1 tbsp brown sugar
½ tsp cinnamon
Crumble Topping
50g all-purpose flour
50g brown sugar
40g cold unsalted butter, cubed
Pinch of salt
Optional: ¼ tsp cinnamon
Instructions
Make the Batter
1. In a large mixing bowl, whisk together sourdough discard, milk or yogurt, eggs, vanilla, and melted butter.
2. In a separate bowl, combine flour, sugars, salt, baking powder, baking soda, and cinnamon.
3. Fold dry ingredients into the wet mixture until just combined. Do not overmix.
Prepare the Apple Layer
4. Toss apple slices with lemon juice, brown sugar, and cinnamon. Set aside.
Make the Crumble
5. In a small bowl, combine flour, brown sugar, salt, and cinnamon (if using).
6. Rub in cold butter with your fingertips until mixture resembles coarse crumbs.
Assemble the Cake
7. Preheat oven to 350°F / 175°C. Line an 8x8” pan with parchment.
8. Pour batter into the pan and smooth the surface.
9. Arrange apple slices evenly over the top.
10. Sprinkle crumble mixture over the apples.
Rest (Optional but Recommended)
11. For deeper flavor and improved crumb, cover and refrigerate the unbaked cake overnight (8–12 hours).
12. If baking immediately, continue to next step.
Bake
13. Bake for 40–45 minutes, or until a toothpick inserted into the center comes out clean.
14. Cool in the pan for 10–15 minutes, then transfer to a rack to cool fully before slicing.
Visual Cues
Top should be golden and crisp with toasted crumble edges.
Interior crumb should be soft and tender, with layers of apple running throughout.
Why This Works
Sourdough discard adds richness and structure to the cake, while the spiced apple and crumble topping create contrast in texture and flavor. It’s a humble, homey bake — elevated with nuance and warmth.
