Banana streusel snack cake

I’m not a huge fan of Jamie Oliver’s recipe names style like “the best ___ ever”, “the ultimate ___”, and so on – taste is such a subjective thing, something fantastic for some people might not be all that for others.
But if you allow me, I’ll be a walking contradiction today and tell you that this is the best banana cake I have ever eaten – it’s a good thing my grandma doesn’t read my blog. :D

Banana streusel snack cake
from Baking for All Occasions

Streusel:
6 tablespoons (60g) all purpose flour
6 tablespoons firmly packed (75g) light brown sugar
3 tablespoons (42g) unsalted butter, softened
¼ teaspoon ground cinnamon

Cake:
1 1/3 cups (233g) cake flour*
1 teaspoon baking powder
½ teaspoon baking soda
½ teaspoon salt
1 cup (255g) mashed ripe bananas (2 medium or 3 small)
3 tablespoons whole milk
1 teaspoon vanilla extract
½ cup (113g/1 stick) unsalted butter, softened
1 cup (200g) demerara sugar
1 large egg, lightly beaten with a fork

Make the streusel: in a medium bowl, mix together the flour, sugar, butter and cinnamon with your fingertips until the mixture is lumpy; refrigerate.
Center a rack in the oven and preheat the oven to 180°C/350°F. Butter a 20cm (8in) square pan then flour the pan, tapping out excess flour. Have all the ingredients in room temperature.
Sift together the flour, baking powder, baking soda and salt into a small bowl and set aside. Put the mashed bananas in a medium bowl and stir in the milk and vanilla; set aside.
In the bowl of an electric mixer fitted with the paddle attachment beat together the butter and sugar on medium-low speed until fluffy, 2-3 minutes. Add the egg and beat until completely incorporated. Add the banana mixture (it will look curdled, but that’s OK) and beat until combined. Reduce the mixer to its lowest speed and gradually add the flour mixture, beating just until incorporated. Spoon the batter into the prepared pan and smooth the surface with a rubber spatula. Sprinkle the streusel evenly over the batter.
Bake the cake until it springs back when gently pressed in the center and a round wooden toothpick inserted in the center comes out clean, 35 minutes. Transfer to a wire rack and let cool in the pan completely before cutting and serving.
The cake is delicious and very, very moist – it will stay that way for 3-4 days if kept in an airtight container.

* homemade cake flour: 1 cup (140g) all purpose flour minus 2 tablespoons + 2 tablespoons corn starch

Serves 16