Can someone please tell me how to make COLORED circles, butterflies, elephants, etc. cake shapes INSIDE a cake?  I've seen a cake with perfectly round circles (different sizes) or butterflies INSIDE the cake.  Need to know if it's a matter of making a different color cake and cutting out the shape with a cookie cutter and setting it inside the cake as I pour the batter in.  When the cake is cut is when you see the design/shape inside each slice.  

Thank you!

Google 'double-baked cakes'