Preheat oven to 350F. Line your pan with parchment, then grease and flour it.
In the bowl of a stand mixer, use the whisk attachment to mix the flour, baking soda, baking powder, and salt until just combined. Add the sugar and mix until combined.
Add the softened butter to the mixture on low until the texture is crumbly.
In a separate bowl, mix the eggs, vanilla, butter flavoring, and caramel syrup. Slowly add to the flour mixture and mix on low speed until combined.
While the mixer is on low, slowly incorporate the buttermilk until smooth.
Add the batter to a 9" cake pan and bake 25-28 minutes, testing the middle with a cake tester or toothpick.
Once the cake is done, let cool in the pans for 10 minutes. Remove cake from pans and let cool completely on a wire rack.
Level the cake with a knife as needed if they are domed.
Brown butter vanilla frosting:
In a medium saucepan over medium-high heat, brown 1/4 cup butter (directions here!)
Once the butter is browned, add the flour to the pot and whisk together.
Slowly whisk in the milk, working out any lumps. Keep whisking while bringing the mixture to a boil so it thickens.
Once boiling, whisk in the vanilla extract and remove the pot from heat and let cool.
While the mixture is cooling, cream together the 1/2 cup butter with the sugars.
Once the flour mixture is completely cool, beat it into the mixing bowl with the sugar mixture. Cream both mixtures together until fluffy.
Put a dab of frosting on your cake plate, then add one layer of cake. Spread frosting over the top of the cake as thickly as you like, then drizzle the butterscotch sauce (recipe here!) over the frosting. Repeat with as many layers as you have.
On the last layer of cake, spread frosting over the top and sides and smooth around the edges and top. Drizzle more butterscotch sauce over the top of the cake, just enough to cover the top and let some drizzle down the sides.
Add any decoration you like such as butterscotch chips and fondant golden snitches (recipe here!)
Makes one 9-inch cake. Double the recipe as needed for extra layers.