Combine the orange zest and juice, water, sugar and cinnamon in a frying pan over medium-high heat and stir to dissolve the sugar. Simmer for 4 minutes or until syrupy. Add the apricot and plum and carefully cook for 1 minute each side. Set aside to cool slightly.
To serve, trim sponge and cut into 4 squares. Halve each piece horizontally. Place sponge bases on serving plates and drizzle with a little fruit syrup and cream. Top with sponge tops. Spread with cream, top with apricot and plum slices and drizzle over syrup. Serve immediately. Serves 4.