For the cupcakes: Preheat the convection oven to 325 degrees F or a standard oven to 350 degrees F.
In large mixer bowl, cream together the granulated sugar, butter and peanut butter until light and fluffy with heavy duty mixer. Add the eggs, one at a time, and mix thoroughly after each addition. Add the vanilla and mix well. Combine the flour, baking soda and salt. Add half of the flour to the mixer bowl along with 1/2 cup of the half-and-half. Mix until the flour is mixed in, scraping the sides of the bowl with a rubber spatula. Add the rest of the flour and the other 1/2 cup half-and-half. Mix until the batter is smooth and all of the flour lumps are gone.
Fill 24 cupcake liners half full and bake for 20 minutes in the convection oven or 28 minutes in the standard oven. The tops of the cupcakes should be lightly browned. Check the cupcakes to make sure no batter sticks to a wooden toothpick when inserted into the cupcake. Cool the cupcakes completely.
For the salted caramel filling: In heavy medium saucepan, cook the granulated sugar by itself over medium-high heat. As the sugar starts to melt, stir continuously until all the sugar is melted and is a dark amber color. Remove from the heat. Stir in the butter until it is completely melted; the mixture will bubble up. Then add the cream and stir until smooth. Sprinkle in the sea salt and stir slightly. Cool to room temperature. Refrigerate until ready to use.
For the peanut butter buttercream: In large mixer bowl, beat together the butter, peanut butter and half of the powdered sugar using heavy duty mixer. Add the half-and-half and the rest of the powdered sugar, along with the vanilla, and mix well. If the frosting is thicker than you would like, add 1 teaspoon of additional half-and-half at a time, mixing well after each addition until the frosting reaches the correct consistency. The thickness may depend on the humidity levels in your region.
To assemble: When cupcakes are cooled to room temperature, make a 3/4-inch hole in the middle of each cupcake using a sharp knife. Leave a small amount of cake in the bottom of each cupcake so that your filling doesn't fall out the bottom of the cupcake. Using a small zipper bag, fill each cupcake to the top with salted caramel filling. Then frost with peanut butter buttercream. You may top cupcakes with chopped peanuts and a salted caramel drizzle as desired.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.