Blueberry Polenta Butter Cake
This easy summer traybake is packed with juicy blueberries and boasts a moist cake crumb thanks to the use of polenta. Perfect for packing up for a picnic.
A summer later, I was still playing with this cake, and it was time to accept the truth: We just loved it so much that I created excuses to make it some more. It’s that kind of cake-dense and buttery, dotted with dreamy berries, portable, quick to make, and infinitely snacky-and I hope it won’t be long until your version of this page is as spattered with berry and batter as mine.
|115g||unsalted butter, at room temperature, plus more for pan|
|125g||plain flour, plus more for pan|
|2 tsp||baking powder|
|½ tsp||table salt|
|¼ tsp||vanilla extract|
|¼ tsp||freshly grated lemon zest|
|200g||blueberries, rinsed and patted dry|
|For the topping:|
|6 tbsp||plain flour|
|¼ tsp||ground cinnamon|
|pinch of||table salt|
|30g||unsalted butter, cut into small pieces|
You will need: a 20cm square tin.
Preheat your oven to 180°/fan 160°C/Gas 4. Line the bottom of a 20cm square tin with parchment, then either butter and flour the bottom and sides, or coat them with a nonstick spray.
Whisk the flour, polenta, baking powder, and salt in a medium bowl, and set aside. Using an electric mixer, beat the butter with sugar in a large bowl until pale and fluffy, for at least 2 minutes. Beat in the eggs one at a time, scraping down the bowl between additions, then add the vanilla and zest. Add a third of the flour mixture, all of the soured cream, and another third of the flour, beating until just blended after each addition. Scrape down sides of the bowl. Mix the remaining third of the flour mixture with the blueberries. Fold the blueberry-flour mixture gently into the cake batter.
Spread the cake batter in the prepared cake tin. Use your original dry-ingredients bowl (see how we look out for your dishpan hands?) to combine the dry topping ingredients with a fork. Mash in the butter with your fork, fingertips, or a pastry blender. Scatter the topping over the batter.
Bake the cake until the top is golden brown and the tester inserted into the centre comes out clean, about 35 minutes. Cool the cake in the tin on a rack for 5 minutes. Run the spatula around the edges of the cake to loosen it, then flip out onto a cooling rack.