The blueberry topping here is added partway through baking so that some of it can sink into the cake to provide a moist filling. Claire Van de Berghe, my trusted recipe tester, reports that her family would like more blueberries in the topping. I like it just the way it is, but if you’re crazy for blueberries, like everyone in the Van de Berghe family, add another ¼ cup (1¼ ounces/35 grams), no more. This cake takes a bit longer than an hour from start to finish, but the result is well worth the extra 10 minutes.
- 1 1/3 cups (6 ounces/170 grams) all-purpose flour
- ¾ teaspoon baking powder
- ¼ teaspoon baking soda
- ¾ teaspoon ground cinnamon
- ¼ teaspoon table salt
- 6 tablespoons (3 ounces/85 grams) unsalted butter, at room temperature
- 1 cup (8 ounces/227 grams) granulated sugar
- 2 large eggs
- 1 teaspoon pure vanilla extract
- 2/3 cup (5½ ounces/156 grams) sour cream
- ¾ cup (3 ounces/85 grams) blueberries, rinsed and well dried
- 3 tablespoons granulated sugar
- 1 tablespoon all-purpose flour
- ½ teaspoon ground cinnamon
1. Position an oven rack on the middle rung. Heat the oven to 350 degrees (180°C). Lightly grease and flour the bottom and sides of a 9-by-2-inch (22.75 cm-by-5 cm) round cake pan, tapping out the excess flour.
2. In a medium bowl, combine the flour, baking powder, baking soda, cinnamon, and salt. Whisk until well blended. In a large bowl, combine the butter and sugar. Beat with an electric mixer (stand mixer fitted with the paddle attachment or hand held mixer) on medium speed until well blended. Add the eggs one at a time and beat just until blended. Add the vanilla with the second egg. Using a rubber spatula, fold the dry ingredients into the butter mixture in 3 batches alternately with the sour cream, beginning and ending with the dry ingredients. Scrape the batter into the prepared pan and spread evenly. Bake for 10 minutes.
3. As soon as you put the cake in the oven, make the topping. In a small bowl, combine the blueberries, sugar, flour, and cinnamon. Mix the ingredients together with a fork, lightly crushing the blueberries.
4. After the cake has baked for 10 minutes, sprinkle the topping evenly over the top of the cake. Continue baking until a toothpick or cake tester inserted in the center of the cake comes out clean, about 30 minutes longer.
5. Transfer the cake to a rack to cool for 10 minutes. Run a knife around the inside edge of the pan to loosen the cake. Using a thick, dry dish towel to protect your hands, invert a large, flat plate on top of the cake pan and, holding both the pan and the plate, invert them together. Lift the pan off the cake. Invert a flat serving plate on the bottom of the cake and invert the cake one more time so that the blueberries are on top. Serve warm or at room temperature.