I'm going to show you how to easily make an impressive striped cake! Following the instructions I've given, a friend of mine who had never baked a cake in his life, using box cake mix, made this cake for his family and everyone was blown away. I found many tutorials on the internet for this style of cake, but most were for a boring chocolate/vanilla cake with thin, wispy stripes. I wanted bold colorful stripes! I want people to see a cake I've made and say "Omg cake!" Then I want them to cut it open and say "OMG CAKE!!!"

Step 1: What You're Going to Need:

You'll need two colors of cake batter. You'll want to add a bit more oil than usual. If your recipe/directions call for half a cup, add about two extra table spoons. Some cake mixes come out too thin. You'll want the consistency of thin pudding. If a box mix says to add a 1 1/4 cup water, I'll only add a cup. You can use a white cake box mix and then separate it into two bowls and add different colors of food coloring to each bowl. I recommend gel food coloring. (And not the crap in the squeeze tubes, it's useless. Try the wilton tubs in the cake decorating section!)
You could also make two different flavors of cake and use them. (Chocolate+strawberry, Lemon+orange, German chocolate+Dark Chocolate etc) The possibilities are endless!

You'll need one large cake pan for a single layer cake or two pans for a layer cake.
Spray your pan well with baking spray!

Step 2: Layering the Batter

Get two spoons the same size, one for each color. Start in the center of the pan and add 2-4 spoonfuls of the first color. The more you use, the thicker your stripes will be. Just be consistent.
Take your next color and add the same amount of spoonfuls of batter, right to the center of the first puddle. Continue building, always from the very center. You'll notice the batter starts to spread towards the edges of the pan. Once my batter reaches the edges, I generally feel like I've used enough batter. You should end with a bullseye!
And seriously, don't try to spread the batter with your spoon EVER. It will end badly. You want to let gravity do the work. Once you get it all in there, you can pick up the pan and give it a nice thump on the counter to force it all to just settle a bit, but that's about it.

Extra batter is a total bonus. Make yourself a little snack.

Bake your cake according to directions. *Usually* about a half hour at 350 degrees, but check your box.

Step 3: Leveling the Cake

You want to wait a little while to level the cake. I suggest putting them on a cooling rack for at least 15-30 minutes.
I stack and decorate my cakes, so I always level them. When your cake comes out of the oven, you should still have a bullseye on top. Probably looking brown and crispy right now, but we can take a peak beneath by leveling that browned dome off.
If you don't own a cake leveling(destroying) device, you can use a bread knife pretty well. Simply score the center of the cake a few centimeters in, then trim the top off in two sections, on each side of your score line. I save my cake tops in the freezer for when I make cake truffles.
Since you have to let your cakes cool, I suggest this is a good time to enjoy your snack.

Step 4: Results

I can't show you the inside of this particular cake because it was for someone else, but here are some others I've made!

These cakes are so easy to make, but look so impressive! They're perfect for children's parties, themed parties and special occasions!

When the cake bakes, the batter rises and the layers we created will sort of rise up from the sides in, so that when you cut the cake, you will get these awesome zebra-like stripes.