Grease and flour 2 x 20cm round cake tins. In a large bowl, cream the butter with sugar. Add eggs one at a time, beating well after each addition. Mix food colouring with cocoa and add to mixture. Add the flour alternately with yogurt, followed by the vanilla and salt. Mix bicarbonate of soda with vinegar, and gently stir into mixture. Do not over mix the cake at this stage. Divide the cake mixture into the prepared tins. Bake in the preheated oven at 170`c for 25 minutes. Allow to cool completely. Meanwhile, make the frosting by beating together 400g icing sugar with 200g butter until light and fluffy. Add in the lemon zest, milk and cream cheese and mix till smooth. Use 2/3 of the mixture to sandwich together the red velvet cake, using sliced fresh strawberries in the layers too. Use the remaining frosting to spread on the top. Decorate with extra strawberries dipped in chocolate and red sprinkles.