90g butter, softened, plus extra for greasing
1 cup plain flour
1 tsp cream of tartar
½ tsp bicarbonate of soda
a pinch salt
1 free-range egg
2-3 tbsp buttermilk or milk
65g caster sugar
6-8 large ripe plums (preferably purple-fleshed, such as a blood plum), halved, stoned and cut into 2-3 pieces
2 tsp pure icing sugar (optional)
double cream, to serve
30g soft brown sugar
½ tsp baking powder
½ tsp ground cinnamon
¹⁄³ cup plain flour
30g unsalted butter, chopped
Preheat oven to 180C. Grease an 18 cm-square cake tin and line base with baking paper, leaving some overhanging to help ease cake out (it can’t be inverted onto a cake cooling rack). Otherwise, grease a 20cm springform cake tin.
To make the streusel mixture, mix sugar, baking powder, cinnamon and flour in a bowl. Rub in butter so mixture is a bit crumbly and lumpy. Set aside.
Sift flour, cream of tartar, bicarbonate of soda and salt into a bowl. Whisk egg with 2 tablespoons of the buttermilk or milk. Cream butter and sugar until pale and thick in a food processor. Tip in flour mixture and pulse to mix quickly. Add egg/buttermilk mixture and process just until you have a smooth batter; it should be a dropping consistency. If it is quite stiff, mix in remaining buttermilk (this will depend on size of egg used).
Scrape butter into prepared tin and smooth the top. Press plum into batter in rows or circles. Scatter over streusel mixture. Bake for 35-40 minutes or until a skewer inserted in the edges comes out clean (it will still test soft in the middle where plum juice has oozed into cake batter). Cool cake in tin on a cake cooling rack until just warm. Lift cake out using overhanging baking paper to assist, then transfer to a plate. Carefully lift base of cake with wide spatula and ease paper out. Dust cake with icing sugar, if desired, and serve with double cream.
Recipe from Stephanie Alexander’s Kitchen Garden Companion, Lantern, RRP $125, 2009