Preheat the oven to 350 degrees. Prepare 12 8 ounce mason jars tins with baking spray.
Sift together the already sifted flour with the salt and the cocoa. Set aside.
In an electric mixer, beat the butter until soft and fluffy. Add the sugar and continue beating until everything is well combined and again, fluffy. Add the eggs one at a time and mix until each is well combined into the batter. Add the vanilla and mix well to combine, scraping down the sides if necessary.
In a separate bowl, whisk together the buttermilk and the food coloring, completely kind of dissolving the dye into the buttermilk (otherwise it will sit on the bottom of the bowl).
You are going to alternately add the flour and the buttermilk to the butter mixture in three parts, beginning and ending with the flour. Keep mixing the entire time, and scrape down the sides of the bowl to make sure that all of the butter and flour are mixed into the red batter.
Now! In a small bowl add the tsp of vinegar. Add the heaping teaspoon of baking soda and mix it with a spoon to combine. It will fizz up, and you should immediately add it to the batter, folding it in with a spatula until well combined.
Immediately spoon the batter into the mason jars. (The batter is pretty thick, so I used an ice cream scooper and it was easier than the spoon I started with). Bake the cakes at 350 degrees for 20 minutes. Pull the cakes out and let them cool before frosting.
¼ tsp salt
⅓ cup sugar
1 cup karo corn syrup
2 Tbsp water
1 Tbsp vanilla bean paste
In the bowl of a standing mixer, whisk the eggs and salt until pale and frothy.
Meanwhile, heat the sugar, corn syrup, water and vanilla paste. Heat over medium flame until the sugar is dissolved and just simmering, about 5 minutes.
With the mixer on medium speed, add a tiny bit of the hot sugar mixture to the egg whites at a time. (Temper the eggs -- don’t scramble them!)
Eventually all of the sugar will be added and then turn the mixer up to high. Beat the mixture on high for about 5 minutes or until very stiff and shiny.
Recipe courtesy of Heather Christo.