Add your eggs and vanilla extract to the butter and sugar mixture. Mix together until completely combined and smooth. Scrape down the sides of the bowl as needed.
Add half of your dry ingredients to the batter and mix until just combined. Do not overmix. Add your milk into the batter and mix until well combined. Mix in your remaining dry ingredients until well combined and smooth. Do not over mix.
Divide the batter evenly between your cakes pans and bake for 22-25 minutes, or until a toothpick comes out almost clean, it should have a few crumbs on it.
Remove your cakes from the oven and allow to cool for about 2-3 minutes in their cake pan, then carefully remove and transfer to cooling racks to cool completely.
Slowly add the melted butterscotch chips and mix until well combined. Mix in about half of your powdered sugar and half of the milk or cream and mix until well combined.
Spread about 1 cup of your frosting into an even layer on top of one of you cakes. Add the second layer of cake on top of the frosting. Spread another cup of frosting on top of that cake and spread into an even layer.