Cut a thick slice off each side of the mango to reveal the large flat central stone. Cut the flesh away from the stone then peel and slice.
Mix the apricot jam with the juice of 1 of the limes then spoon into the base of an 18 x 28 cm (7 x 11 inch) roasting tin lined with nonstick baking paper (see
Put the lime rind and rest of the juice in a mixing bowl or a food processor, add the remaining ingredients and beat until smooth. Spoon over the top of the fruit and spread the surface level. Bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 30–35 minutes until well risen, the cake is golden and springs back when gently pressed with a fingertip.
Leave to cool in the tin for 10 minutes then invert the tin on to a wire rack, remove the tin and lining paper and leave to cool completely. Cut into 20 pieces and serve warm with whipped cream. This is best eaten on the day it is made.