Preheat oven to 350 F. Prepare 3 x 8" cake pans with parchment paper. In bowl of standing mixer, sift all dry ingredients. Add all remaining ingredients to bowl with the dry ingredients and with paddle attachment on mixer, mix for 2 minutes on medium speed and pour into prepared pans. Batter will be liquidy.
Bake for 20 minutes and rotate pans in oven (if not cooked in convection oven). Cakes are done when toothpick or skewer comes clean, approximately 35 minutes.
Place marshmallows on cookie sheet lined with parchment paper. Place in the oven, and broil marshmallows until nice and brown. Keep an eye on them as they burn very quickly. Combine butter and icing sugar in standing mixer fitted with paddle attachment, on low until blended (about 1 minute). Add vanilla and mix on high for about 3 minutes. Add marshmallow cream and toasted marshmallows, and mix on lowest setting for about 1 minute.
Malted Belgian Chocolate Frosting
In a bowl of a standing mixer fitted with paddle attachment, combine the powdered sugar and butter and beat on low speed for about 1 minute. Add vanilla and malt powder, and beat on low until well combined. Add the melted chocolate and beat on medium speed until smooth (about 2 minutes). Add whipping cream and beat on med-high speed for another minute. Best used right away.
*The malted chocolate frosting isn't my favorite, It isn't bad though. I'm a lover of freshly made Swiss meringue or French butter cream, nothing compares to those two!
Prep the pan; Line an 8-inch-square baking pan with parchment paper, allowing it to drape over 2 sides, then brush the paper lightly with oil.
Boil the sugar.
In a deep saucepan, combine 1/4 cup water, the sugar and corn syrup and bring them to a boil over medium-high heat. Boil until the mixture is a warm golden brown. Don't stir -- just swirl the pan.
Heat the cream.
In the meantime, in a small pot, bring the cream, butter and 1 teaspoon of fleur de sel to a simmer over medium heat. Turn off the heat and set aside.
Finish the caramel.
When the sugar mixture is done, turn off the heat and slowly add the cream mixture to the sugar mixture. Be careful -- it will bubble up violently. Stir in the vanilla and vanilla bean paste with a high heat resistant spatula and cook over medium-low heat for about 10 minutes, until the mixture reaches 248 degrees F (firm ball) on a candy thermometer.
Fill the pan.
Very carefully (it's hot!) pour the caramel into the prepared pan and refrigerate for about 30 minutes or until firm.
Cut the caramel.
When the caramel is cold, pry the sheet from the pan onto a cutting board. Cut the square in half.
Roll it up.
Starting with a long side, roll the caramel up tightly into an 8-inch-long log.
Cut into pieces.
Sprinkle the log with fleur de sel, trim the ends and cut into 8 pieces. (Start by cutting the log in half, then continue cutting each piece in half until you have 8 equal pieces.) It's easier to cut the caramels if you brush the knife with flavorless oil like canola oil.
Wrap the candies.
Cut parchment paper into 4-by-5-inch pieces and wrap each caramel individually, twisting the ends. Store in the refrigerator and serve the caramels chilled or at room temperature (if you can wait.)