Butterscotch Cake with Caramel Icing

1 . Stage

Preheat the oven to 350 degrees F (175 degrees C). Grease and flour two 9-inch round cake pans, or line with parchment paper.

2 . Stage

Combine brown sugar and butter for cake in a bowl; cream with an electric mixer on medium speed until fluffy. Add vanilla extract, then add eggs, one at a time, beating on low speed just until they are mixed in.

3 . Stage

Sift flour, baking soda, baking powder, and salt together in a separate bowl. Add flour mixture in 2 batches, alternating with buttermilk, beating batter on low speed until well mixed, scraping down the bowl by hand as needed. Pour batter evenly into the prepared pans.

4 . Stage

Bake in the preheated oven until a toothpick inserted into the center of each layer comes out clean, 25 to 30 minutes. Cool on a wire rack for 5 minutes. Run a table knife around the edges to loosen. Invert carefully onto a serving plate or cooling rack. Let cool, about 30 minutes.

5 . Stage

While cake cools, combine brown sugar, 1/4 cup butter, milk, and flour for icing in a small saucepan over medium heat; bring to a boil. Continue to boil, stirring frequently to prevent burning, for 1 minute. Remove from heat and stir in 2 tablespoons butter and vanilla extract. Cool the mixture, stirring occasionally, until it is still warm (but not hot) and has thickened enough to spread.

6 . Stage

Spread icing over the cake, moving fairly quickly because it will set as it cools. It will be a thin coating, not a thick layer. Let set completely before cutting into the cake.