Preheat the oven to 350 degrees F. Grease and flour 2 9-inch cake pans lined with parchment paper.

In a large bowl, use an electric mixer to cream together shortening and sugar until light and fluffy (about 5 minutes). Add the eggs, one at a time, beating well after each addition. Add the vanilla and butter flavoring; mix until fluffy.

In a separate bowl, whisk together flour, baking powder, baking soda and salt.

With the mixer on low, alternately add the flour mixture and the buttermilk, beginning and ending with the flour mixture, beating until well blended.

Beat the batter for 5 minutes on medium speed.

Divide the batter evenly between the two prepared pans. Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean. Cool cakes on a wire rack for about 10 minutes, then remove from pans and cool completely before icing. Once the cake is cool, use a long serrated knife to trim the cake layers if they have domes on top. You want a flat, even surface on the top of each cake.

Melt the butter in a medium saucepan over low heat. Add the brown sugar and whisk to completely combine. Bring to a gentle boil and let the mixture bubble for 2 minutes, stirring constantly with a whisk. Carefully and slowly add the milk (it will bubble up), stirring constantly, until the mixture comes to a full, rolling boil. Remove from heat. Transfer mixture to the bowl of a stand mixer that’s fitted with a whisk attachment.

With the mixer on low speed, gradually add the sifted confectioners’ sugar, mixing until smooth. The icing should look glossy and will pour easily from the bowl.

While the icing is still warm, frost the cooled cake layers by spreading the icing between the two cake layers first, then on the top and sides of the cake. The icing will set up as it cools. If the icing gets too hard while you’re frosting the cake, just microwave the icing in 10-second intervals until it’s smooth again.