For the cupcakes: Preheat the oven to 350 degrees and line cupcake pans with paper liners. Combine the flour, baking soda, baking powder and salt in a bowl and set aside.
In a large bowl, cream the butter until light and fluffy. Add your sugars and beat until well-combined. Beat in the eggs, one at a time, mixing well after each addition. Then beat in your vanilla and butter flavoring.
Alternately add in the buttermilk and cream soda into the dry ingredients in batches until all are well incorporated. Fill each cupcake liner 3/4 full, then bake for 15 to 17 minutes until a tester inserted into the center comes out clean and cake springs back to the touch. Cool completely on wire racks.
For butterscotch filling: In a double boiler (heat-proof bowl over a pot of simmering water on the stove), combine butterscotch chips and heavy cream and stir until completely combined and smooth. Cool to room temperature. Fill a squeeze bottle with ganache and insert into the center of each cupcake, squeezing until filling begins to overflow.
For buttercream frosting: Cream butter in a large bowl until light and fluffy. Add in the prepared ganache, vanilla, butter flavoring and salt and mix until well combined. Beat in powdered sugar, 1 cup at a time, until reaching desired consistency. Add milk or cream by the Tablespoon as needed. Frost cupcakes and top with a drizzle of butterscotch ganache.