Cut the edges of the loaf to make it as round as possible, then slice it in the middle to make 2 layers (or 3 if you like).
To make the frosting, beat all of the frosting ingredients together using a hand mixer or stir with a spatula. If the frosting is too thick, thin it out with sour cream or milk.
Thinly slice smoked salmon, cucumber, egg, radishes and carrots.
To assemble the sandwich cake, lightly spread the cream cheese frosting on the first layer of bread.
Then add smoked salmon, followed by cucumber, sliced egg, radishes, carrots and peas.
Cover with the second layer, and spread a layer of cream cheese frosting on top.
Frost/cover the whole sandwich cake the same way you frost a dessert cake by covering the sides of the cake.
Finally, decorate cake with salmon roses, and the rest of the ingredients.