Cupcakes: Preheat oven to 350 degrees and line cupcake pans with liners. Combine flour, baking soda, baking powder, and salt in a bowl and set aside. In a large bowl, cream butter until light and fluffy. Add sugars and beat until well combined. Beat in your eggs, one at a time, mixing well after each addition. Then beat in vanilla and butter flavoring.
Alternate adding your buttermilk, cream soda and dry ingredients in batches until all are well incorporated. Fill each cupcake liner 3/4 full, then bake 15-17 minutes or until toothpick comes out clean from the center. Cool completely on wire rack.
Buuterscotch Filling: In a double boiler, combine butterscotch chips and heavy cream and stir until completely combined and smooth. Cool to room temperature. Fill a squeeze bottle w/ganache and insert into the center of each cupcake, squeezing until filling begins to overflow.
Buttercream Frosting: Cream butter in a large bowl until fluffy. Add in the ganache, vanilla, butter flavoring, and salt and mix until well combined. Beat in the powdered sugar, 1 cup at a time until reaching the desired consistency. Add milk or cream (I prefer cream) by the tbsp. as needed. Frost cupcakes and top with a drizzle of the butterscotch ganache.