For the chocolate cupcakes: Preheat the oven to 350 degrees F. Line a 24-cup muffin pan with cupcake liners.

Cream the granulated sugar, butter and oil in a large bowl. Beat in the eggs, one at a time, until fluffy. Add the vanilla and blend well. Sift the flour, baking soda and sea salt and gradually add to the sugar mixture, alternating with the milk.

Whisk the cocoa and water until smooth in a small bowl. Add to the mixture and continue beating until well blended.

Fill each muffin cup three-quarters full with batter. Bake the cupcakes until baked through the center, about 15 minutes. Remove the cupcakes from the pan and cool on wire racks.

For the chocolate fudge filling: Melt the butter in a microwave-safe bowl. Whisk the cocoa and water until smooth in a separate bowl. Whisk the cocoa mixture into the butter until blended and smooth. Whisk in the powdered sugar until fluffy. Yield: 2 cups.

For the buttercream base frosting: Whip the powdered sugar, milk, vanilla and sea salt with a whisk attachment on low until smooth and creamy. Add the butter one slice at a time until well blended. Add the shortening and blend well. Whip on high until the mixture doubles, 10 to 12 minutes. Yield: 8 cups.

For the salted caramel: Combine 1/4 cup room temperature water and the granulated sugar in a small saucepan. Cook over medium-low heat until the sugar dissolves. Increase the heat to medium-high and bring to a boil. Boil without stirring, until the mixture is approximately 325 degrees F and a deep amber color, 5 to 6 minutes.

Remove the caramel from the heat and whisk in the cream. The caramel will bubble violently. Once smooth, stir in the butter and fine sea salt. Transfer the caramel to a heat safe container and allow cooling for 15 minutes. Cover and refrigerate for up to 2 weeks. Yield: 1 1/2 cups.

For the salted caramel frosting: Whip 2 1/2 cups buttercream base frosting, the powdered sugar and 1/2 cup salted caramel with a whisk attachment until fluffy. Yield: 3 cups.

Once the cupcakes are cool, cut out the center of each cupcake and fill with the chocolate fudge filling. Top each cupcake with the salted caramel frosting.