Preheat the oven to 360°F/ 180°C. Line the bottom of the springform pan with parchment paper.
Rhubarb: Wash, dry, and peel the rhubarb. Cut it into small pieces, about ¾ inch (2 cm). Place the pieces in a large bowl, add sugar, cornstarch, and vanilla extract, and mix well. Set aside while you prepare the batter.9 oz rhubarb + 1 tablespoon granulated sugar + 2 tablespoons cornstarch + ½ teaspoon vanilla extract
Wet ingredients: Beat the eggs, sugar, and salt with an electric mixer until pale and creamy, about 4-5 minutes. 2 large eggs + ½ cup + 2 tablespoons granulated sugar + 1 pinch of salt
Add the vanilla extract and lemon zest and mix briefly. Add sour cream and oil and stir shortly until combined.½ teaspoon vanilla extract + 2 teaspoons lemon zest + ⅓ cup + 1 tablespoon sour cream + 6 tablespoons neutral-tasting oil
Dry ingredients: Mix flour and baking powder in another bowl. Fold them gently into the wet ingredients using a spoon or rubber spatula until just combined. Don’t overmix the batter.1 ⅓ cups + ½ tablespoon all-purpose flour + ¾ teaspoon baking powder
Assemble the cake: Pour the batter into the prepared springform pan. Spoon the rhubarb pieces evenly on top, leaving the accumulated juices behind in the bowl.
Bake the sour cream rhubarb cake for about 50 minutes or until a skewer inserted into the center comes out clean. If the cake browns too quickly, cover it loosely with aluminum foil during the last part of the baking time.
Leave the cake to cool completely in the springform pan. Dust it with confectioners’ sugar before serving.1 teaspoon confectioners’ sugar
Notes
Measurements: I recommend using a digital kitchen scale for weighing the ingredients; it guarantees the best results.
Dairy: You can also use full-fat Greek yogurt instead of sour cream.
Oil: Make sure it is neutral-tasting. I always use canola oil, but sunflower oil, vegetable oil, or grapeseed oil are also good choices.