Instructions: Preheat oven to 350 degrees ..

Place the orange pieces in a saucepan and cover with water. Bring to the boil and simmer for 30 minutes until the orange is softened. Drain, transfer to a food processor and whirl until smooth. Set to aside.

Line an 8 x 8" square baking pan with baking parchment.

In a bowl mix together the orange pulp, sugar, egg whites and yogurt.

Sift the flour, baking powder and cocoa and lightly fold together.

Transfer the mixture to the prepared pan and gently level off.

Bake for 30 minutes until risen and firm. Allow to cool in the pan for 5 minutes then transfer to a wire rack to cool.

Cut into 9 equal squares and lightly dust with icing sugar.

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