A few weeks ago, I made my nephew his birthday cake. He loves Assassin's Creed, an historical video game series that features lots of daring do, sword fights and maps of Rome and Constantinople. So I made him a theme cake, using the symbol from the game. For simplicity's sake, I'll just explain the decorating techniques here. I used two nine inch rounds of white sponge cake (made with vanilla extract and greek yogurt to cut sweetness) and a filling of strawberry jam cooked with honey, cardamom, and a vanilla bean with lemon juice at the finish. I made a standard white eggless buttercream (butter, icing sugar, vanilla and whole milk). I used an icing spatula and a dough cutter, dipped in very hot water, to finish the surface of the cake.
I used red and black fondant (commercial) for the decorations. To make the Assassin's symbol, I used a printed stencil and cut the fondant with a paring knife:
My niece helped make the molded fondant rosettes. Note: always oil that mold and don't let the fondant get too warm, or it will stick.
I then added the birthday number to the top of the cake, and we were ready to go!
As you can see from the cross section, the cake rose well and the filling is nice and even.