So on the day of his party, I got the cake out and I cut it in half to make 2 layers.  I then put the bottom layer onto a cake board and set the other layer off to the side while I made the frosting.  I went with a vanilla buttercream because that is what he wanted but chocolate would have worked too.
 After the frosting was made I assembled the cake by putting frosting on the bottom layer and then putting the top layer on top.  I then did a crumb layer with frosting to hold in all the crumbs to make frosting easier when I went to decorate.

 This is a really helpful step to getting a nice finish on a cake.  It makes it so much easier to frost and decorate if you put just a thin layer of frosting on the cake first.  it doesn't have to be perfect, just slap some of the frosting on and spread it with a spatula.  You just want to trap all of those crumbs in so when you go to frost it, the crumbs don't get mixed into the frosting. Then you chill it for about 20 minutes until the frosting is nice and set. While the first layer of frosting was setting on the cake, I went and dyed the rest of the buttercream black.
 When you use food dyes, you really need to be careful to read your labels.  It seems like all food dyes should be gluten free but that is not always the case.  Wilton products are not reliable because there is a cross contamination warning so I never use their products.  Their fondant is also not gluten free so just try to steer clear of any of their stuff.  It is hard because they are so big and their products are the easiest to find.
 Anyway, just dye the rest of the frosting black and then frost the cake with the rest of the buttercream. I used a piping bag to get it on the cake but that is really not necessary.  You can just spoon it on or use a spatula.  It is just really quick and easy to get it on the cake in an even layer when you use a piping bag. Just make sure the frosting is on in a nice and even layer.  You may have to chill it and then go back and smooth it out again to get a good finish.  That is what I had to do.  I chilled it and while I was chilling it, I started working on the fondant.
 Now, you can make fondant and I have.  You can make fondant out of marshmallows and powdered sugar but for this cake I didn't need a lot of it so I just bought it.   You can buy a lot of fondant or at some places you can just buy a small package of colored fondant.  I went that way because it just seemed like the easiest way to go and most cost efficient.  I bought some blue, red and black fondant and it was the perfect amount to make this cake. You just roll it out with some cornstarch or powdered sugar.  It can get pretty sticky so make sure that you are dusting your surface really well.
 I rolled out the blue and the red in a big strip and then applied it to the sides of the cake to get the look of the Nintendo Switch controllers. It was pretty easy.  I used a ruler to make sure that I was getting a straight line and then put it on the the sides of the cake.  I saved the extra blue and red fondant for the letters.  After the blue and red fondant was on I worked on the black fondant to make the controller buttons. I cut out the rest of the buttons out of the black fondant and then applied it to the cake. It wasn't very hard and I just used what I had in my kitchen.  I used a lot of piping tips to cut the buttons out and it worked pretty well.
The last thing that I did was cut the letters out of the leftover fondant.  I didn't really know what to put in the middle of the cake.  A lot of people that I saw did the Nintendo logo there but I thought it would be nice to put Happy Birthday on the cake.  I got some fondant cutters at Hobby Lobby and used them to cut out the letters.  It was so easy! I am not good at cute handwriting and I didn't trust myself to be able to write it in buttercream so I went with the fondant and I think it is going to be my go to way to write happy birthday on cakes.

All in all, I was really pleased with how it turned out.  I definitely think that the cake looks homemade but it also looks how I wanted it too.  My 9 year old was really excited and he was so excited to show his friends when they came over for his party.  The best part was that it tasted amazing! I made the cake and buttercream from scratch so it was a really delicious cake.  It did turn everyone's mouths black but boys that age really didn't mind.  It was really fun to make and got me thinking of the next fun cake that I want to make and try and perfect my cake making skills.