Preheat the oven to 350 degrees F. Place 24 cupcake liners in a cupcake pan.

In a large bowl, mix together the flour, granulated sugar, milk, cocoa, vegetable oil, vanilla extract, salt and eggs. Mix until smooth. Add the baking soda to 1 cup water. Add baking soda mixture to the batter. Mix well (the batter will be thin). Pour the batter into baking cups, filling three-quarters of the way up. Bake for 12 to 15 minutes.

To assemble: Place the Caramel in a pastry bag fitted with a small tip. Push the tip through the bottom of paper liner to fill each cupcake. Add the Whipped Frosting to a pastry bag fitted with a large tip. Pipe a swirl of the frosting onto each cupcake, covering the filling. Sprinkle the Toffee over the frosting. Transfer the cupcakes to the refrigerator and chill for at least 30 minutes.

In a large saucepan, stir together the granulated sugar, milk, butter, 2 teaspoons vanilla extract and the salt. While stirring, bring to a boil. Cook for 7 minutes. Remove from the heat, and stir in the remaining teaspoon of vanilla extract. Let cool.

Chill the bowl of a stand mixer in the freezer.

Add the heavy cream to the chilled bowl. Whip with the whisk attachment on medium-high speed until soft peaks form. Add the confectioners' sugar and continue to whip until thoroughly combined and stiff peaks form. Be careful not to over beat. Blend in the vanilla extract.

Spray a large cookie sheet with nonstick spray.

Combine the butter, granulated sugar and 1/2 cup water in a heavy pan. Stir constantly at a simmer until the mixture turns brown (like a brown paper bag). Pour the mixture onto the prepared cookie sheet. Break the chocolate bar onto the toffee while still hot. With the back of a spoon, spread the chocolate evenly. Let cool and then break into small pieces.