Heat the oven to 190C (170C fan) or Gas 5 and grease and line two 20cm sandwich tins.
Put the sugar, butter, eggs, elderflower cordial, self-raising flour and baking powder in a bowl and mix together with an electric mixer until pale and creamy, about 2 minutes.
Pour into the sandwich tins and bake for 15-20 minutes until risen and pale golden. The cake should spring back when pressed. Let the cakes cool in the tin for 10 minutes, and then transfer to a wire rack to cool completely.
For the filling, beat together the butter and a third of the icing sugar in a bowl with an electric mixer until creamy. Add 2tbsp of the rhubarb conserve and mix to combine, then gradually mix in the remaining icing sugar and beat for 2 minutes until pale and fluffy.
Spoon the rhubarb icing into a piping bag, cut the tip of the piping bag to the size of a 20p coin. Spread the remaining 2tbsp of rhubarb conserve on the bottom of one of the sponges, then pipe half the icing on top before sandwiching the second sponge on top. Pipe the remainder of the icing on the top of the cake. (Of course you can just spread the icing if piping seems like too much of a faff).
Serve as is or decorate further with chopped pecans, dried rose petals or even candied rhubarb.
WhatIWoreToday.com founder and lifestyle commentator, Poppy Dinsey rather fell in love with this cake at the Summer launch of our new Bonne Maman Rhubarb Conserve. The subtle flavour of this voluptuous cake appealed to her many fans on poppyd.com, so we felt we should share here too.
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