Heat oven to 160C/140C fan/gas 3. Use a little of the lactose free butter to grease a deep 23cm cake tin and line with baking parchment. Mix the raspberries and 50g of the polenta, then set aside.
In a large bowl, combine the lactose free butter and sugar with an electric whisk until pale and fluffy. Add the eggs, one at a time, mixing well between each addition.
Add the remaining polenta, the almonds, gluten free baking powder, gluten free flour, lactose free yogurt, orange blossom water, orange juice and raspberry mix, and stir everything until just combined.
Tip into the tin, smooth the top and bake for 45 mins or until a skewer comes out clean.
When the cake is done, remove from the oven. Leave to cool in the tin for 20 mins, then transfer to a wire rack to cool completely.
To make the raspberry icing, put the raspberries and icing sugar in a small food processor and blend until smooth. Cover all over the cake, then top with whole raspberries. Will keep for up to 5 days in a cake tin.