To make the cupcakes, heat oven to 350º and line cupcake pans with liners.

In a medium bowl, whisk together the flour, baking soda, baking powder and salt and set aside. In the bowl of a stand mixer fitted with the paddle attachment, cream the butter on medium speed until light and fluffy. Add both sugars and continue beating until well combined. On low speed, add eggs one at a time, beating well after each addition.

Combine the schnapps and buttermilk. Add the dry ingredients in three batches, alternating with the cream soda and buttermilk. Mix until just combined, scraping the sides and bottom of the bowl as needed.

Fill each cupcake liner about ¾ full, then bake for 15-17 minutes until a toothpick inserted in the center comes out clean. Cool completely on a wire rack.

While the cupcakes are cooling, make the filling by combining the butterscotch chips and heavy cream in a glass bowl set over a pot of simmering water. Stir occasionally until combined. Remove from heat and allow to cool to room temperature. Transfer to a squeeze bottle and fill each cupcake just until the filling comes to the top.

To make the frosting, cream the butter on medium speed until light and fluffy. Add the butterscotch filling, schnapps and salt and beat until well combined. On low speed, beat in the powdered sugar one cup at a time until desired consistency is reached. Add cream soda as needed to thin the frosting. Frost cupcakes and drizzle with remaining syrup.