Preheat the oven to 200 degrees C. Lightly grease a 20cm round cake tin that is about 4cm high. Sprinkle it with the brown sugar. Lay the pineapple slices flat over the base and fill any gaps with cherries, with the cut side facing upwards.
Beat together the eggs and sugar until light and fluffy, then beat in the creme fraiche. Sift the flour and baking powder over the mixture and fold in gently but thoroughly.
Carefully pour the batter into the tin, making sure not to dislodge the fruit. Bake for 35–40 minutes until well risen and golden brown and springy to the touch.
Leave the cake to cool in the tin for 5 minutes before turning out onto a serving plate, so that the pineapple is uppermost. Serve warm with creme fraiche or cream.