Preheat oven to 350° F. Prepare 2 standard muffin pans by lining with 24 paper cupcake liners. Set aside.

Sift the flour, sugar, cocoa, baking soda, baking powder, and salt into the bowl of an electric mixer fitted with a paddle attachment and mix on low speed until combined. In another bowl, combine the buttermilk, oil, eggs, and vanilla. With the mixer on low speed, slowly add the wet ingredients to the dry. With mixer still on low, slowly and carefully add the coffee and stir just to combine, scraping the bottom of the bowl with a rubber spatula. The batter will be very loose.

This original recipe is for 2 round pans, and I found this amount to be just a bit too much for 24 cupcakes, so I remove about 1 cup of batter before dividing amongst the cupcake liners.

Bake for about 18 to 20 minutes, or until a toothpick comes out clean. Let cool in the pans for 15 minutes, then move to a cooling rack to cool completely.

Place cream in a small bowl. Scrape in seeds from vanilla bean and then also add the bean. Set aside.

Stir sugar, corn syrup, and water in a heavy saucepan over medium heat until sugar dissolves. Increase heat to medium-high and bring to a boil, occasionally swirling pan and brushing down sides with a wet pastry brush. It will thicken and turn deeper in color. After about 5 to 6 minutes, it should be deep amber in color. Don't let it get too dark. If it starts to smell burnt, immediately remove pan from heat.

Gradually add vanilla cream, while continuously whisking. The mixture will bubble vigorously. Whisk over medium heat until smooth and thick, about 2 minutes. Remove from heat and whisk in butter and salt. Strain into a heatproof bowl. Place in refrigerator to cool completely.

In a stand mixer fitted with a paddle, beat the butter until creamy. At low speed, beat in the powdered sugar. Increase the speed to high and beat until fluffy, scraping down the side of the bowl, about 2 minutes longer.

At low speed, beat in the cream and vanilla. Then gradually beat in the 1-1/4 cup of cooled caramel sauce. Scrape down the side of the bowl and the paddle, increase the speed to medium-high and beat until light, 3 minutes longer.

Using a wooden spoon, vigorously beat the buttercream for 30 seconds to deflate any air bubbles.

Fill pastry bag with a large star tip and pipe buttercream onto cupcakes. Drizzle over the top of each one a bit of the remaining salted caramel sauce. (Any leftover salted caramel sauce is wonderful over vanilla ice cream!)

Press a chocolate coated espresso bean into each swirl of frosting and then sprinkle lightly with sea salt.

Serve immediately or store in a container in the refrigerator. Remove from refrigerator about 30 minutes prior to serving