Preheat oven to 180C
Line a 23cm square tin with parchment.
Cook the rhubarb with the maple syrup in the tin for 10 minutes at about 180C (in a conventional oven) or until cooked, then add the strawberries to the rhubarb.
Make the Victoria sponge, adding the grated orange rind to the mixture. Spoon the sponge mixture over the fruit and bake for 25 minutes, also at 180C, until cooked.
Cool before turning out and serve with crème fraîche.