Crumble topping:
1/2 cup brown sugar
1/2 cup flour
1/2 teaspoon cinnamon
1/2 teaspoon nutmeg
1/4 cup butter, softened
Cake:
2 cups flour
2 teaspoons baking powder
1/4 teaspoon salt
1/2 teaspoon cinnamon
3/4 cup sugar
1/4 cup butter, softened
1 large egg
1 teaspoon vanilla extract
1/2 cup buttermilk
3 cups frozen aronia berries
Preheat the oven to 190 C. Grease a 29 cm2 square pan and set aside. In a medium bowl, combine the first 6 ingredients, mixing together with a fork until crumbly; set aside. In another medium bowl, stir together the flour, baking powder, salt and cinnamon.
In a large bowl, cream together the remaining butter and sugar. Blend in the egg and vanilla until smooth. Blend in the flour mixture and cream alternately, beginning and ending with the flour (flour, milk, flour, milk, flour). Fold in the Aronia berries. (The dough is quite stiff, so be patient as you’re folding in the berries! Don’t mush them up!)
Spread the batter into the prepared pan and sprinkle with the crumble topping. Bake for 50-60 minutes, until a toothpick inserted in the center of the cake comes out clean. Cool, and cut into 9 large squares.