Cake Mix Turned Fantastic!

I just got this book this week and it is SO fun! I have an addiction that can only be cured by making cupcakes for everything I can think of. I just made an Easter egg basket bunch for a baby shower, which-- of course I didn't take any pictures of. But I tried out a tweaked recipe that was awesome!
Perfect Cake-Mix Cupcakes
"You can use any standard cake mix, but avoid those with pudding in the mix and steer clear of lighter cake mixes such as angel food cake, since cupcake projects need a firm cake that will hold up when it's decorated. If you don't have buttermilk on hand, you can make a fair substitution by adding 1 tablespoon lemon juice to 1 cup whole milk. Let it sit for about 10 minutes to sour. (Actual buttermilk is better!)"

1 box cake mix
1 c. buttermilk (in place of the water called for on the box)
vegetable oil (the regular amount on the box)
4 large eggs (in place of the number called for on the box)

1. Preheat oven to 350*F. Line 24 muffin cups with paper liners.
2. Follow the box instructions, putting all the ingredients in a large bowl and using the buttermilk in place of the water specified (the box will call for more water than the amount of buttermilk that you are using), using the amount of vegetable oil that is called for (typically, white or yellow cakes call for 1/3 c.; the chocolate cakes usually call for 1/2 c.), and adding the eggs. Beat with an electric mixer until moistened, about 30 seconds. Increase the speed to high and beat until thick, 2 minutes longer.
3. Spoon half of the batter into a ziplock bag. Snip a 1/4" corner from the bag and fill the paper liners 2/3 full. Repeat with the remaining batter. Bake until golden and a toothpick inserted in the center comes out clean, 15-20 minutes. Remove the cupcakes from the baking pans, place on wire rack and allow to cool completely.

* I learned that you should never open the oven door to peek at the cupcakes before 15 minutes is up or you will let the air out and they will sink!!
**I also learned that you need to always use room temperature butter when making your own cake mix, and to always cream it together thoroughly.
***But when it comes to mixing the wet and the dry, only mix until it is combined.
****Lastly, always tap the bottom of your cupcake pan to get any air bubbles out so they will puff up nice and even!!