Equipment
Ingredients
Fruit Preparation
- 350 g fresh rhubarb, trimmed and cut into 1cm pieces
- 15 g all-purpose flour
Dry Ingredients
- 250 g all-purpose flour
- 4 g baking powder
- 2 g baking soda
- 3 g fine sea salt
Wet Ingredients
- 115 g unsalted butter, room temperature/softened
- 200 g granulated sugar
- 1 large egg, room temperature
- 5 ml vanilla extract
- 240 ml buttermilk, shaken well
Topping
- 30 g demerara or turbinado sugar
Nutrition (per serving)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 367 kcal
- Protein
- 6 g
- Carbohydrates
- 58 g
- Fat
- 13 g
- Fiber
- 2 g
- Sugar
- 31 g
- Sodium
- 325 mg
- Saturated Fat
- 8 g
- Monounsaturated Fat
- 4 g
- Polyunsaturated Fat
- 1 g
- Cholesterol
- 55 mg
- Potassium
- 220 mg
- Calcium
- 114 mg
- Iron
- 0.7 mg
- Magnesium
- 17 mg
- Phosphorus
- 95 mg
- Zinc
- 0.5 mg
- Vitamin A
- 115 mcg
- Vitamin C
- 4 mg
- Vitamin D
- 0.1 mcg
- Vitamin E
- 0.6 mg
- Vitamin K
- 14 mcg
- Vitamin B6
- 0.0 mg
- Vitamin B12
- 0.1 mcg
- Thiamin
- 0.06 mg
- Riboflavin
- 0.11 mg
- Niacin
- 0.6 mg
- Folate
- 17 mcg
- Water
- 79 g
- Alcohol
- 0 g
Sources: USDA FoodData Central
Method
Preheat the oven to 175°C (350°F). Grease the 23cm (9-inch) cake pan with butter and line the bottom with parchment paper.
In a small bowl, toss the chopped rhubarb with the 15g of flour. This coating prevents the fruit from sinking to the bottom of the cake during baking.
In a medium bowl, whisk together the 250g flour, baking powder, baking soda, and salt until well combined.
In a large bowl or stand mixer fitted with the paddle attachment, beat the softened butter and granulated sugar on medium-high speed until pale and fluffy (about 3-4 minutes).
Add the egg and vanilla extract to the butter mixture. Beat until fully incorporated, scraping down the sides of the bowl as needed.
Reduce mixer speed to low. Add the flour mixture in three parts, alternating with the buttermilk in two parts (dry-wet-dry-wet-dry). Mix only until the flour streaks disappear to avoid toughening the gluten.
Gently fold the flour-dusted rhubarb into the thick batter using a spatula. Transfer the batter to the prepared pan and smooth the top.
Sprinkle the demerara sugar evenly over the surface of the batter.
Bake in the center of the oven for 45-55 minutes. The cake is done when the top is golden brown and a tester inserted into the center comes out clean (internal temperature approx 93°C/200°F).
Let the cake cool in the pan for 15 minutes, then run a knife around the edge and invert onto a rack to cool completely.
Chef's Notes
- Room temperature ingredients are critical for this method; if the buttermilk or eggs are cold, the butter will seize, leading to a grainy batter.
- If you cannot find buttermilk, mix 240ml of whole milk with 15ml of lemon juice or white vinegar and let sit for 10 minutes.
- For a more 'pastry' like finish, you can dot the top with small cubes of cold butter before sprinkling the sugar.
- Serve warm with a dollop of unsweetened whipped cream to balance the sweet cake and tart fruit.
Storage
Refrigerator: 5 days — Cover tightly to prevent drying out. Bring to room temperature before eating.
Freezer: 3 months — Wrap individual slices in plastic wrap and foil.
Reheating: Warm gently in a low oven or microwave for 10-15 seconds to refresh the crumb.
Troubleshooting
Cake is dense or rubbery
Cause: Overmixing after adding flour or ingredients were too cold
Fix: Cannot be fixed, but can be served warm with custard to mask texture.
Prevention: Stop mixing as soon as flour disappears; ensure butter, egg, and buttermilk are at room temperature.
Rhubarb sank to the bottom
Cause: Batter was too thin or fruit wasn't coated in flour
Fix: Invert the cake and serve it 'upside down' fruit-side up.
Prevention: Ensure the fruit is tossed in flour before adding; do not reduce the flour quantity in the main batter.
Cultural Context
Rhubarb, often called the 'pie plant,' was popularized in early American and British baking as one of the first crops to appear in spring. This cake style mimics the simplicity of a 'buckle' or 'slump,' dishes designed to highlight seasonal produce without fussy technique.
