I took my inspiration from Kerry-Sue B. in Ontario, Canada. Thank you for submitting your cake to coolest birthday cakes. However, I did not have the time to make the trip to find the suggested cake pan. I improvised and was very happy with the results of this monkey cake.
I started with two 9" round cakes. One was slightly thicker than the other, but that wasn't necessary (just an opps). One round is left whole. Using the cake pan as your guide, slide it about 1 1/2" to 2" from the top center and trace the pan cutting a moon shaped sliver out of the second 9" round. Place the moon at the top of the whole round. Next, I used my small 3" Pyrex bowl open side down and cut a small circle tracing the bowl. I cut the circle in half and placed one semi-circle on either side of the head for ears. With my uneven cakes I had to thin the semi-circles. I cut a second 3" circle for the nose & mouth area. This circle only needs to be about 1/2" thick. I added a small trapazoid to the top of the nose mouth area for a more distinct nose. The bow at the monkey's ear was made with the thinned circle pieces of the circles and a small rectangle between them.
I heeded Kerry-Sue's warning about the melty frosting, but didn't want to make my own. I bought a pint of butter cream icing from the Walmart Bakery for $5. Using the Wilton brown color gel, I tinted the frosting to the desired shade. Outline the general monkey face with a Wilton #3 line tip. I started piping the stars with the darker outside frosting, but learned I should have started with the center lighter brown first. That way you don't have to change bags and mix more frosting to add the details of the eyes, ears and smile in darker brown. You also won't lean on the already piped stars around the outside. The stars are made with a Wilton #16 star tip. The eyes are piped with a #18 star tip, but they could be done with the #16 tip as well. The bow is Wilton Pink color gel piped in the same fashion as the Monkey. Personalize if you wish.
I have never made a cake like this and it was a great experience. I was very pleased with the results as was my little girl. However, it did take me 3+ hours to cut and frost. Allow plenty of time, be patient with yourself, and have fun.