Step 1

Preheat the oven to 350 F, and position a rack in the center of the oven.

Step 2

Thoroughly grease a 10 cup bundt pan, such as the "Jubilee" bundt pan, with non-stick baking spray.

Step 3

In a large bowl, sift together the flour, baking powder, salt, spices and espresso powder, then whisk until well combined.

Step 4

Separately, whisk together the milk, vinegar, brown sugar, molasses, eggs, melted butter, oil and vanilla.

Step 5

Add the liquid ingredients to the dry, and whisk until combined and mostly smooth. Pour the batter into the prepared pan.

Step 6

Bake the cake for about 40-45 minutes, until a cake tester inserted in the cake comes out clean.

Step 7

Cool the cake in the pan for 15 minutes, then turn the cake out onto a cooling rack. Remove the pan and let the cake cool completely before decorating with buttercream.

Step 8

In the bowl of your stand mixer fitted with the paddle attachment (or with a hand held electric mixer), beat the butter for 1 minute until smooth.

Step 9

With the mixer on low, add the powdered sugar, meringue powder and salt, mixing until combined. Add the vanilla.

Step 10

Increase the speed to medium and whip for 4-5 minutes, scraping the bowl down several times, until light and fluffy.

Step 11

Fit a 16-inch disposable piping bag with a coupler and tip #32 (small star tip). Fill half full with the buttercream.

Step 12

Set the cooled cake on a serving plate or cake pedestal.

Step 13

Starting at the bottom of the cake, pipe "shells" along the diagonal ridges of the cake, as shown in the photos. Complete the bottom row before moving up the sides of the cake to the next row. Finish with a shell border around the base of the cake.