Rhubarb Cake With Rhubarb Sauce
Bake a tender Rhubarb Cake With Rhubarb Sauce — sweet brown sugar cake topped with a glossy, tangy rhubarb sauce.
Ingredients
- 1 ½ cups (300 g) light brown sugar, (packed)
- ⅔ cup (145 g) vegetable oil
- 2 large eggs, (room temperature)
- 1 cup buttermilk
- 1 teaspoon kosher salt
- 1 teaspoon baking soda
- 1 teaspoon vanilla extract
- 2 ½ cups (312.5 g) all-purpose flour
- 1 pound rhubarb, (diced (about 3 cups))
- 1 pound rhubarb, (cut into ½-inch pieces (about 3 cups))
- ¼ cup water
- ⅓ cup (67 g) granulated sugar
Instructions
Step 1: Preheat the oven and prepare the pan
Preheat the oven to 350°F and spray a 9×13-inch baking dish thoroughly with nonstick cooking spray so the cake releases cleanly after baking. While the oven warms, set the prepared rectangular baking dish on the white quartzite surface and have a small spatula and the whisk nearby — ready for the batter.
Step 2: Whisk wet ingredients, add flour, fold in rhubarb
In a large mixing bowl, whisk together the packed light brown sugar, vegetable oil, eggs, buttermilk, kosher salt, baking soda, and vanilla until smooth and slightly glossy. Gently stir in the all-purpose flour just until combined — don’t overmix; you want a tender crumb. Fold in the diced rhubarb pieces so they’re evenly distributed, then scrape the thick, speckled batter into the prepared 9×13 pan and smooth the top with a spatula.
Step 3: Bake and let the cake cool
Bake the batter for 45–50 minutes, or until an inserted toothpick comes out with a few dry crumbs but no wet batter. Remove the rectangular pan and allow the cake to cool on the quartzite surface until it’s warm-to-touch and stable enough to top; cooling makes the sauce hold on the surface rather than sink in.
Step 4: Make the rhubarb sauce and finish the cake
In a saucepan combine the cut rhubarb, water, and granulated sugar and bring to a boil, then simmer until the rhubarb breaks down into a glossy, chunky ruby sauce (about 10–15 minutes). Let the sauce cool slightly off-heat so it thickens a bit, then spoon the vibrant rhubarb sauce over the cooled cake in the same rectangular vessel so the ruby syrup pools in shallow rivulets across the top.
Notes
- Use firm, brightly colored rhubarb stalks for best flavor and texture.
- Pat rhubarb dry after cutting to avoid thinning the batter.
- Do not overmix the batter; fold until just combined for a tender crumb.
- If using frozen rhubarb, thaw and drain well before adding to batter.
- Store cake in an airtight container in the refrigerator for up to 4 days.