Delicious scratch-made Butterscotch Cake features super moist and tender brown sugar cake layers, filled with thick homemade butterscotch sauce, all finished with butterscotch buttercream. The perfect fall cake!
In a medium bowl whisk together the flour, baking powder, salt, and cinnamon.
In a large bowl with an electric mixer, beat the butter on high speed until smooth and creamy, about 1 minute. Add the sugars and beat on high speed for 3 to 4 minutes, until light and fluffy. Add vanilla and eggs and beat on medium-high speed until combined.
With the mixer on low speed, add the flour mixture in three additions alternating with the sour cream, beginning and ending with the flour, mixing just until combined. Do not overmix. Batter will be thick.
Pour into prepared pans and bake for 35 minutes, or until golden brown and a toothpick comes out clean. Let cool for 20 minutes in pans before turning out onto a cooling rack. For easier frosting, freeze the cake layers until firm.
Make the frosting:
In the bowl of a stand mixer fitted with the paddle attachment, mix together the sugar and butter. Mix on low speed until well blended and then increase the speed to medium and beat for another 2 minutes. Add the salt, vanilla, and 1/3 cup of the butterscotch and beat on medium for 2 minutes, or until thoroughly combined.
Assemble the cake:
Cut each cake layer in half using a wire cake leveler or a sharp serrated knife.
Place one cake layer on a cake turntable or cake stand. Spread about 1/3 cup of butterscotch sauce all over cake layer, leaving a 1/2-inch border at the edges. Repeat with the remaining cake layers.
Place the last cake layer upside-down onto the frosting so that the top of the cake is nice and flat. With an offset spatula, crumb coat the assembled cake by spreading a thin layer of frosting evenly all over the cake, scraping off any excess like spackle. Refrigerate for 30 minutes or freeze for 15 minutes until the crumb coat frosting layer is firm. Smooth on the remaining frosting and decorate as desired.
Serve or cover and store in the fridge for up to 2 days. Let come to room temperature for an hour before serving.