This adorable cake is every little girl's dream! And you don't need to be a professional cake maker to do it. You really don't.

What you will need, though, is time. Thankfully, much of this project can be prepped weeks before it's assembled and served.

What you need for this project:

Ingredients for preferred cake & buttercream icing
Ingredients for home-made fondant (easy and so much cheaper than store-bought)
Some nice quality food coloring (gets the colors more vibrant)
A new, disposable small paint brush
Rainbow nonpareils
Sugar Pearls
One or two 9-in cake pans (the regular size) (If you only have one, you'll just use it twice.)
One or two 6-in cake pans (If you only have one, you'll just use it twice.)
One 9x12-in rectangular pan
Two 12-in cardboard cake circles
One small dowel (full length, choose a small diameter size you can cut with kitchen scissors)
Ponies! You can get the little ones, perfect for decorating a cake, on Amazon here. (They also make great party favors if you are going for a theme.)

Step 1: Make an Army of Flowers. (Do Ahead)

Make fondant.
Choose any recipe you prefer. I like Holly's recipe here. If you want to save time, you can make 2 batches of it now. Wrap the other batch in plastic wrap, and refrigerate it until you need it.
Divide dough in half, then divide each half into three. Knead in food coloring into each sixth: red, orange, yellow, green, blue, and purple. Set aside about a 1/3 cup of each color for making the rainbow.
Roll out the red dough with a fondant roller.
Punch out flowers with fondant cutter.
Place one pearl in the center of each flower. If the pearls don't stick, dab a tiny dot of water* on the center of the flower with the paintbrush before placing the pearl.
Place flowers on wax paper to dry.
Repeat steps 3, 4, 5, and 6 for each color.

After they harden, layer the flowers on wax paper in a tupperware container, cover, and keep on counter or in a cabinet until needed. Flowers will keep, un-refrigerated, for up to two weeks. Do not store in fridge--the humidity will make them sweat and goo-ify.

To roll and cut the flowers, I used the tools at the top of the page.

*A tiny dab of water on fondant will act like glue. Take care to not use too much water, or your colors will run and it'll get messy quick.

Step 2: Make Rainbow Topper. (Do Ahead)

Take the fondant you set aside from the flowers, and roll out each color into an equal diameter-sized tube.
On a sheet of wax paper, center a small drinking glass. Loop your Purple fondant tube around the glass, leaving a couple inches of length on each side to give the rainbow height.
Brush a tiny amount of water onto the upper edge of the purple fondant, and layer the blue fondant tube over the purple.
Repeat steps 5 and 6 with each color until the rainbow is complete.
Remove the glass, cut the ends of the rainbow so each color is even with its neighbor.

Leave the rainbow topper to set on your countertop for a day or two. Try not to move it until it's completely hard. After it hardens, place the rainbow in a tupperware container, cover, and keep on counter or in a cabinet until needed. Rainbow topper will keep, un-refrigerated, for up to two weeks. Do not store in fridge--the humidity will make it sweat and goo-ify.

If cracking occurs, brush tiny amounts of water to glue the cracks together.

Step 3: Bake Cakes. (Do Ahead If You Have Room in Your Freezer.)

You can bake cakes up to a month in advance, if you have room in your freezer to store them. If not, make them a day or two at most before the party.

Choose your cake recipe. I like this recipe (just the cake, not the mousse).
Mix two batches according to instructions.
Line your 9-in and 6-in pans with butter, flour, and if you're like me, a circle of parchment paper at the bottom to make sure those little cakes don't stick!
Divide batter into two 9-in pans and two 6-in pans.
(I did mention earlier you can use one of each pan type. If you only have one 6-in pan, you'll need to bake one cake, let it cool, take it out of the pan, and then bake the other.)
Bake according to recipe. For the 6-in cakes, they'll cook about 10 minutes faster than the bigger cakes. Take them out early. Test with a toothpick to make sure they're done.
Set on rack to cool, then remove from pan to cool completely.

If making the cakes in advance, wrap them in plastic wrap and then foil, and place them in the freezer until you need them. Take them out a couple hours before you're ready to decorate.

Step 4: Assemble Lower Cake.

You can assemble the cake up to a day before you plan to serve it.

Make fondant. If you made 2 batches when you made flowers, take your second batch out of the fridge to use now. Knead in blue food coloring, and set aside.
Make buttercream icing. Flavor as desired.
Place one 9-in cake on a 12-in cardboard cake plate (or your preferred serving plate). Spread a layer of buttercream over the top, and place second 9-in cake on top.
Shape top cake as needed with a breadknife. It should be flat, not rounded.
Layer buttercream over the flattened top and sides of 9 in cake.
Place blue fondant on large sheet of wax paper, roll out evenly, large enough to drape over entire lower cake. Transfer to cake using wax paper and large cutting board, if needed. Remove wax paper. Smooth any lines and trim the bottom of the fondant to meet the cake plate.
Add your tier stilts:
Cut your dowel to the height of the lower cake. Make four height-sized pieces.
Mark four places, a couple inches from the center of the cake (see above diagram). Punch the dowels through the marks, all the way to the bottom. If necessary, pull the dowels out a bit and re-cut so they are flush with the top of the cake.

Continue with Assembling Upper Cake.

Step 5: Assemble Upper Cake.

You can assemble the cake up to a day before you plan to serve it.

Make buttercream icing. Flavor as desired. Do not color.
Place one 6-in cake on a cutting board. Spread a layer of buttercream over the top, and place second 6-in cake over.
Shape top cake as needed with a breadknife. It should be flat, not rounded.
Layer buttercream over sides of 6-in cake.
*Do not put buttercream on top of the cake, yet!*
Empty your rainbow nonpareils into a clean 9x12-in rectangle pan.
Pick up 6-in cake, holding one hand on top and the other on the bottom, and roll the sides of the cake in the nonpareils until nice and covered. Return to cutting board.
Layer buttercream icing on top of cake. pour remaining rainbow nonpareils onto top of cake. Cover evenly.

Continue with Placing Upper Cake, Flowers, Rainbow, and Ponies.

Step 6: Place Upper Cake, Flowers, Rainbow, and Ponies.

Cut second cardboard cake plate to a diameter of 6 inches.
Place upper cake on small cake board, and center over dowels on lower cake.
Using a pastry bag, plastic bag, or cake decorator, bead buttercream icing on the seam between the two cakes and along the bottom edge of the lower cake.
Using your paint brush and a glass of water, glue your rainbow flowers in a wave design to the bottom layer of your cake.
*Remember, don't use too much water! Just a tiny bit will glue the flowers on.*
Bead two large "clouds" of buttercream on top of upper cake, and place rainbow in the cloud centers. Use toothpicks to prop the rainbow up until the buttercream sets.
Place small ponies on the edge of the lower cake. Bead small clouds under feet to stick them to the cake.
Place large pony on top of cake. Bead small clouds under feet to stick it to the cake.

Serve day today or tomorrow. Come back and post a picture! I'd love to see how your cake turned out.

Happy birthday and have fun!