Preheat oven to 170° (fan assisted). Line the base and sides of a 23cm square cake tin with baking paper. Mix together chopped feijoas, blueberries, sugar and Gregg's Ground Ginger and set aside.
Prepare the crumble topping. Put ground almonds, flour, wholegrain oats and sugar into a mixing bowl. Stir through melted butter. Set aside.
Prepare the shortcake. Beat together butter and sugar until pale. Beat in the egg. Mix in flour and baking powder to form a soft dough. Press dough evenly into the base of the prepared tin.
Spoon over the prepared fruit to cover the base. Scatter over the crumble mix.
Bake for 40-45 minutes until top is golden and base cooked. Leave in the tin for 20 minutes before carefully lifting it out, with the baking paper onto a cake rack to cool. Serve cut into pieces with yoghurt, ice-cream or cream.
Replace fresh blueberries with frozen blueberries
To make lining the tin with baking paper easier - grease the base and sides with a little oil or melted butter.