Copycat Krispy Kreme Doughnuts are fabulously light and fluffy and literally melt in your mouth. Covered in a wonderfully sweet glaze, these overnight yeast doughnuts are every bit as delicious as "Hot" Krispy Kremes.
Combine yeast and warm water in a glass measuring cup. Add 1/2 teaspoon of sugar. Let sit 10 minutes.
In the bowl of a stand mixer, combine sugar, melted butter, egg, egg yolk and salt. With the paddle attachment, beat just until combined.Add yeast and beat until combined.
Add flour and beat on medium-low speed until dough starts to pull away from sides of bowl. If necessary, add another tablespoon or two of flour. Dough should be sticky, so don't add too much flour.
Brush the top of the dough with oil. Cover and let rise until doubled in bulk, about 1 to 1/2 hours.
Punch dough down, cover with plastic wrap and refrigerate overnight.
On a lightly floured surface, roll dough out until it is about 1/2-inch thickness.Use a doughnut cutter to cut doughnuts and place them and the doughnut holes on a piece of parchment or wax paper.You can reroll the scraps and cut more doughnuts, but they will be a little misshapen when they fry. Or you can cut a bunch of doughnut holes out of the scraps.
Cover doughnuts with a towel and let rise for 1 hour.Prepare glaze. Whisk together all ingredients in a shallow bowl until smooth. Set aside.
Heat shortening in a Dutch oven or deep cast iron skillet until 360 degrees.Working in batches, fry 3 doughnuts at a time for about 1 minute per side. Drain on paper towel lined plate and then dip in glaze. Place on a wire rack set inside a baking sheet.Fry the doughnut holes, drain and dip in glaze.
If you don't have bread flour, you can use all-purpose flour.