Surprise Cake: Rainbow/Sunset/Tie-Dye on the Inside Cake

I was looking for easy but fancy cakes to make for events at the end of 2015 (my annual gingerbread party, the work holiday potluck lunch, and a co-worker's retirement day) and my first thought was "bundt cakes are always fancy!"  That might sound silly, since it is only a difference in pan shape, but you would be amazed how often I have had people ooh and aah over a regular cake-mix cake made in a bundt pan.  

And then I thought about cakes that look plain, but have a surprise inside.  After all: who doesn't love a surprise inside?!  (I think that the great unknown of prizes-in-cereal-boxes when we were kids makes this statement true for pretty much everyone in my generation....)  Since I was looking for something easy that also uses a regular pan and equipment, a lot of the "surprise" cakes that are out there in places like Pinterest weren't really the right fit.  However, the idea of a tie-dye or rainbow cake was perfect.  I found several sets of instructions that used only one batch of cake batter, including one for a Christmas wreath cake from Betty Crocker.  But then I found this Halloween version that uses 1 3/4 batches of cake batter, and is chocolate on the outside and vanilla on the inside.  Since the finished cake is bigger, it seemed perfect for special events.  

I used the basic idea of the Halloween cake, but made it my own.  I made one Christmas one that was chocolate outside and red, green, and white vanilla on the inside.  Then I used white and green vanilla drizzle and Christmas colored sprinkles on top.  It was pretty nifty.  

The one pictured below was for my co-worker's last day at work before she retired.  I made it with pink, orange, and yellow: sunset colors.  The drizzle on top was milk chocolate frosting and it was pretty darn amazing!

Obviously, you could use whatever flavors and colors you want, but here are the instructions, with my notes:

Ingredients:

• 1 box white cake mix
• 1 box chocolate cake mix: I used chocolate-fudge for the one pictured here 
• Water, oil, and eggs as called for on the 2 cake mix boxes: I used the egg-whites-only option for the white cake so the colors would be as true as possible
• Food coloring
• Can of frosting: I used milk chocolate

Cake Instructions:

1. Heat oven to 350 degrees (or the temperature called for on the cake mix boxes)
2. Grease bundt cake pan well. I used Pam spray to quickly and easily get into all the grooves.
3. Mix up your cake mixes (in separate bowls, obviously)  according to the directions on the boxes.
      
4. Separate the white cake batter into smaller bowls
   
5. Color white cake batter. I made three colors in even amounts, but you could also leave one white or have one color be "bigger" than the others.
   
6. Take out about 1/4 of chocolate batter (1 to 1 1/4 cups?) and set aside.  You will not use this batter.  (Using all the batter from 2 mixes would probably overflow the pan.  1 3/4 mixes makes for a really, really full standard bundt cake pan.)
7. Pour about 2/3 of the remaining chocolate batter in prepared pan
8. Spoon one color of vanilla batter into pan, carefully adding it just to the middle.  This means that--as much as possible--leave a visible line of chocolate batter around the outside and around the middle.
   NOTE: As you spoon the batter in a ring, the batter-in-total will seek a balance.  This means that the chocolate batter will rise on the outside and around the middle, ensuring that the outside of the finished cake will be even chocolate.  
   
9. One at a time, spoon in the other colors on top of the first one.  Do not stir the colors together or try to mix them!!
     
10. Pour the rest of the chocolate batter on top and smooth it over the colors.
    
11. Bake cake, following bundt cake directions, until a cake tester comes out clean.  It might take a bit longer than a normal bundt cake, but probably not much more. 
12. Let cool for a few minutes, then shake pan to loosen cake and turn it out on a plate to cool entirely.  When on a plate, cake should look completely chocolate on the outside.
    
    

Drizzle Instructions:

1. When cake is completely cool, spoon some of frosting into a microwave-safe bowl.  
2. Heat for a very short period of time.  Try 8 or 12 seconds at first.
3. Stir to get a smooth, drizzle-able consistency (heat a few seconds more if needed)
4. Take spoon and drizzle at will!
   
5. Be prepared for people to gasp when you cut the first piece of cake!