Preheat oven to 350 degrees and line two regular muffin tins with 18 paper liners
In a large mixing bowl, combine flour, salt, baking powder and baking soda and stir until combined
In a separate large mixing bowl, combine melted butter and sugar and stir until smooth. Butter should be melted but not hot.
Add, yogurt, vanilla extract, milk and eggs to the butter mixture and whisk until just combined.
Add the dry ingredients to the bowl with the wet ingredients and fold with a spatula until just combined.
Using a three tablespoon cookie scoop, fill each muffin cup with one full scoop of batter. Do not overfill.
Place a one teaspoon sized dollop of Nutella on top of each batter filled cup and swirl slightly with a toothpick.
Bake at 350 degrees for 20 minutes or until a toothpick comes out clean. You may have Nutella on the toothpick but you should not have wet batter come out.