Preheat oven to 350°F. Line a 12 cup muffin tin with muffin liners. Set aside.
In a mixing bowl, sift the flour. Add in salt, baking powder, and baking soda. Set aside.
1 ¾ cup All-purpose flour, ½ teaspoon Salt, 1 teaspoon Baking powder, ½ teaspoon Baking soda
Using a mixer, beat the butter and sugar. Beat on high for 3 minutes. It will be pale and fluffy. Add in sour cream, vanilla, and eggs. Beat on high for 2 minutes. It will appear lumpy, but that is normal.
¾ cup Unsalted butter, ¾ cup White granulated sugar, 2 Large eggs, ¼ cup Sour cream, 1 teaspoon Pure vanilla extract
Add in ⅓rd of the dry ingredients and half of the buttermilk. Add in another ⅓rd of the dry ingredients and the rest of the buttermilk. Finish with the rest of the dry ingredients. Scrape the bowl.
½ cup Buttermilk
Heat Nutella in a microwave safe bowl for 20 seconds. Stir.
½ cup Nutella
Use 1 Tablespoon or a cookie scoop to scoop the batter. Spoon a ½ teaspoon of Nutella on to each cupcake. Use a toothpick to swirl the Nutella. Fill the muffin tin ⅔rds full of cupcake batter. Add another ½ teaspoon of Nutella and swirl the top.
Bake the cupcakes for 18-22 minutes. The cupcakes are done baking when a toothpick inserted comes out clean. Let them cool for 10 minutes. Transfer to a cooling rack. Cool completely before decorating.