Step 3: Coat the rice crispy hill in chocolate.
You will also need to pull out the ramekin before you do this step.
With a sharp knife, cut jagged pieces of "land" right at the "shoreline" of the rice crispy hill. You can heat the knife to make it cut better.
Step 4: Test fit the rice crispy hill on the cake.
Test fit the pieces and trim to fit.
Remember where all the pieces went. Use a digital camera for this step.
Step 5: Frost the cake.
Top the cake with the hill and the jagged pieces of "land".
I microwaved a little of the frosting for 10 seconds so it was slightly warm and pourable. I poured it around the area of the ramekin opening, and let it dribble down the side of the hill.
Step 6: Make the sides, and added effects.
Melt more chocolate and "weld" the top and side pieces together.
For the platform that R2-D2 is standing on, get a sour cream container lid, or any lid with some structural relief (little plastic ribs in the structure for interest). Lightly butter, or spray some non-stick cooking spray, inside the lids. Use these as moulds for melted white chocolate.
As an added bonus, I got some blinking lights from the cake decorating section at Walmart. These are supposed to be attached to the stems of Champagne glasses, etc. I made a couple of moulds out of a measuring spoon, and the center of an apple slicer/corer. I buttered them well and poured more white chocolate in them. Once they started cooling down I insterted the blinking lights in the white chocolate. Once completely cooled down I popped them out of the molds and used them on the cake.