Rhubarb Cake With Rhubarb Sauce

Make Rhubarb Cake With Rhubarb Sauce: a tender sheet cake glazed with tangy rhubarb sauce, ready in about 75 minutes.

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 and prepare the pan

Preheat the oven to 350°F and generously spray a 9×13-inch rectangular baking dish with nonstick cooking spray so the cake will release cleanly. Set the prepared pan aside on the Luna Pearl granite surface while you assemble the batter.

Step 2: Whisk the wet mix

In a large, modern matte grey ceramic mixing bowl, whisk together the packed light brown sugar, vegetable oil, two room-temperature eggs, buttermilk, kosher salt, baking soda, and vanilla until smooth and slightly glossy. Work with a gentle, steady rhythm so the mixture becomes homogenous but not overworked.

Step 3: Stir in the flour

Add the all-purpose flour to the wet mixture and stir with a flexible spatula just until combined. Stop when the dry streaks disappear—aim for a thick, tender batter with a few small air pockets but no dense overmixing.

Step 4: Fold in rhubarb and transfer to the pan

Gently fold the diced rhubarb into the batter so the pink flecks are evenly dispersed, then scrape the batter into the prepared 9×13-inch baking dish, smoothing the top with an offset spatula. The batter should sit slightly lumpy with visible rhubarb pieces ready to bake.

Step 5: Bake and cool

Bake the cake until a toothpick inserted into the center comes out with a few moist crumbs but no wet batter, about 45–50 minutes. Remove from the oven and allow the cake to cool in the pan while you move on to the sauce.

Step 6: Simmer the rhubarb sauce

In a medium saucepan, combine the sauce rhubarb pieces, water, and granulated sugar and bring to a simmer. Cook until the rhubarb breaks down into a glossy, slightly chunky sauce (about 10–15 minutes), then remove from heat and let it cool until slightly thickened and spoonable.

Step 7: Finish and serve

When the cake is cool, spoon the slightly cooled rhubarb sauce evenly over the top so it glazes the surface. Serve a neat rectangular slice—maintaining the sheet cake geometry—on a matching rectangular plate, topped with a round scoop of vanilla ice cream beginning to melt and a few swirls of whipped cream, garnished with a couple of fresh rhubarb stalks and a soft beige cloth casually visible beside the plate.

Notes

• Use room-temperature eggs for even mixing and better rise.
• Trim and dice rhubarb uniformly so it disperses evenly in the batter.
• If the cake seems dry after refrigeration, warm a slice and spoon extra sauce over it.
• For a richer flavor, swap half the oil for melted butter.
• To keep the sauce from becoming too thin, simmer gently until slightly thickened before cooling.