For the cake:

1. Thoroughly mix all ingredients together.
2. Divide the batter between two 7-inch or two 8-inch prepared pans.
3. Bake at 325° for about 38-45 minutes just until a toothpick comes out clean. 
4. Allow cakes to cool in the pans for 10 minutes, then flip out onto a cooling rack to finish cooling.
    

For the frosting:

1. First, add the butter and shortening to the mixing bowl and cream together. Scrape down the sides to be sure that it’s completely mixed together.
2. NOTE: I put my bowl on the scale, zero it, then add the shortening and weigh it. I do this for 2 reasons – it’s more accurate than trying to measure messy shortening in a measuring cup AND it’s one less greasy cup to wash!
3. Add the vanilla and butter flavors and mix again.
4. Slowly add in the powdered sugar, a little at a time until completely incorporated. This will take time and might make a mess. I like to drape a damp towel completely over the top of my mixer to "catch" the powdered sugar dust. Again, scrape down the sides of the bowl often.  UPDATE: Now that I use a Bosch mixer, I don't have the huge mess or need the damp towel. It's all kept in the bowl ... YAY!  See my post about that here.
5. When all of the sugar has been added, start adding tablespoons of milk or cream to “thin” the frosting to the desired texture. I usually use milk unless I happen to have cream in the frig, but either works just fine. I make a fairly thick icing to cover and fill cakes and make it slightly thinner to decorate.  
6. You can use this immediately or keep in the fridge in an airtight bowl for up to 2 weeks. It can also be frozen for several weeks. If you’re using it out of the fridge, make sure its completely thawed and rewhip, adding milk as needed to get the desired texture again.

Assemble the cake:

1. Place the first cooled cake layer on a cake board or cake plate, 
2. Add frosting to the top of that layer, then place the second layer of cake on top.
3. Frost the entire cake, then smooth it with a bench scraper and small offset spatula.
4. Chill the cake for at least an hour, or 30 minutes in the freezer.

For the drip:

1. Open the can of frosting and remove the foil seal.
2. Microwave in 10-second intervals and stir in between each until the frosting is pourable.
3. If you have a food thermometer, it's best to get the frosting to 100°F-102°F.
4. Using a spoon or squeeze bottle, apply the frosting to the top edge of the thoroughly chilled cake.
5. Decorate with piping, candy, sprinkles, etc.