Other materials:

• 570 gram of unsalted butter
• 335 ml of water

Preheat the oven to 180°C (convection oven 160°C). Make 500 gram of Mix for Cupcakes as indicated on the package or in this basic recipe.  Fill a greased baking pan with the batter and bake in the middle of the oven for approx. 65-70 minutes. Then prepare 640 gram of Mix for Brownies following the indications on the package or in this basic recipe. Fill the baking pan with the batter and bake in the middle of the oven for 45-50 minutes. Let it cool down on a cooling grid. Prepare 200 gram of Mix for Buttercream as indicated on the package or in this basic recipe. Flavour one third of the buttercream with the strawberry flavouring, this will be the ketchup. The rest of the buttercream will stay natural to be used to cover the cake and as mayonnaise.

Roll out the yellow fondant very thinly to make cheese. Cut out rectangular shapes using the cutting wheel. Use the front and back of decorating tip #12 to cut little cirkles out of the rectangles. Make as much as you like to add to the hamburger.
For the tomato roll out the red fondant until a thickness of 4 mm and cut out rounds. Make as many as you think you’ll need. Roll out white fondant for the onions, again until a thickness of 4 mm and use the cutting wheel to cut out little moons. Make as many as you like. 
Finally make the lettuce out of green fondant. Roll out the fondant thinly and cut out cirkles which you place on the foam pad. Work the bone tool along the edge so it start to curl. Make as many as you like.

Cut the cake in half and round the top a bit with a sharp knife. Cover the outsides of the two halves of the cake with buttercream. Knead the chocolate fondant and roll it out until a thickness of 3 mm. Cover the round cutted upper cake of the hamburger with it. Knead the rest of the chocolate fondant and roll a long strip of it which you’ll use to cover the side of the bottom cake. Fold the edges inwards. Add a thick layer of natural buttercream on the bottom cake, this being the mayonnaise. Place the lettuce, cheese, tomato and onion and then the brownie on top of it. Add a thick layer of strawberry buttercream on top of the brownie, this being the ketchup and place the lettuce, tomato, cheese and onion on top of it again. Finish it with the top of the cake. 

For the sesame seeds knead a piece of white fondant with a piece of chocolate fondant and make little balls of it. Roll this to a drip and push them flat. Stick the seeds on top of the upper cake using a bit of edible glue.