Preheat the oven to 160C and line three 7inch cake tins. I greased then floured the tins or you can line with greaseproof paper.
Cream the margarine, vegetable oil and sugar together with the lemon zest and whole chia seeds.
Squeeze the lemon juice into a measuring jug and make up to 400ml with the dairyfree milk.
Weigh out the flour and fold into the creamed mixture while drizzling in the lemon & milk.
Divide the batter equally into the tins and sprinkle over the crushed frozen raspberries. Gently swirl into the batter.
Bake on the middle shelf for between 25-28minutes. You will want to check the cakes after about 20minutes and then every couple of minutes after that.
When completely cool, layer with buttercream and leave to set. Once the filling has set, cover the sides and top of the cake with a thin layer of buttercream. If you are feeling really fancy you can pipe pretty roses or just add a smooth layer and decorate with fresh raspberries.
Add all the ingredients for the buttercream into a large mixing bowl and beat together until smooth & fluffy. This is much easier with an electric mixer but start slow and increase the speed once the icing sugar is mixed in otherwise your kitchen will disappear in clouds of icing sugar!
*The recipe says 300ml but you may need more or less depending on how much juice you get out of the lemons. You need 350ml of liquid altogether.