In mixing bowl combine flour, sugar, salt, nutmeg, and baking powder. Mix on low with paddle attachment until combined
Add butter and mix on medium speed until combined until incorporated.
In a separate small bowl, whisk together egg, buttermilk, sour cream and vanilla. Slowly add to flour mixture and mix on medium. Do not over mix – all you need is 45-60 seconds. The dough will be sticky.
Cover the dough and let it rest for 20 minutes. Meanwhile, bring your oil to temperature (360 to 375 degrees).
Roll out the dough on a floured surface to 1/2 inch thick. Cut doughnuts using a “doughnut cutter” or a large and small biscuit cutter.
When the oil reaches temperature, begin to fry your doughnuts. Fry until golden brown (about 45 seconds per side). Place doughnuts on cooling rack covered with plenty of paper towels.
Dip doughnuts in the chocolate glaze. Sprinkle with vanilla sea salt. Allow to rest for the glaze to set.