This homemade Roller Skate birthday cake is a double layer, 8" cake, frosted with buttercream frosting. I tinted a portion of frosting in Sky Blue and used a fat star tip to put polka dots around the outside of the cake, as well as a rope border around the bottom and top. I then tinted a small portion of frosting in Violet, and put purple centers on the polka dots and around the top border with a small star tip (a Wilton #16 is what I used).
I filled in the entire top of the cake with bright blue sanding sugar. For the skate, I cut a boot-shaped piece of wax paper and placed it on another piece of wax paper. You will need two of these. I melted some white candy melts in a decorating bag and cut the tip off the bag. I drizzled the candy melts back and forth, diagonally in both directions, to make the lattice pattern. It won't matter if this goes off the edges. Before the candy hardens, I lifted the boot-shaped wax paper off the other wax paper and placed it aside to harden.
To make the four wheels, I piped melted candy melts into a small circular cookie cutter on wax paper. Once the boots and wheels have hardened, remove them from the wax paper. I used melted candy to glue two sucker sticks between the two boot-shaped pieces, letting them stick out about 3" so you can use them to stick into the cake. Also I used some melted candy to glue the two boots together at the top. Once hardened, I stuck the whole thing into the cake. I then used melted candy to glue on the wheels, front and back. I used blue and purple frosting to make shoe laces and decorations on the skate.