Into large bowl, add 1 1/2 cups flour. Set aside.
Place chocolate in double boiler over hot, not boiling, water. Melt chocolate.
When chocolate has melted add to flour.
Add 1 1/4 cup sugar, vanilla, buttermilk, eggs, shorting, baking powder, baking soda and salt. Beat with a mixer at low speed, just until smooth, constantly scraping bowl.
Then at medium speed, beat 1 minute, constantly scraping bowl.
Add in remaining flour. Beat gently to make soft dough.
Cover and place in refrigerator for at least 1 hour, to make dough easier to handle.
Flour a large work surface and rolling pin.
Roll dough out to 1/2-inch thick.
Using a floured doughnut cutter, cut out doughnuts.
Reroll and cut trimmings until all dough is used.
Pour oil into a deep fryer to a depth of about 3 to 4 inches.
Heat oil to vegetable oil to 350°F as measured by a candy thermometer.
When oil is hot, gently place 4 or 5 dough rings at a time into oil. Do not crowd.
Turn with a pancake turner as they rise to surface. Then turn often until golden brown.
Lift doughnuts from oil with slotted spoon. Place on a paper towel-covered plate to drain.
Repeat until all doughnuts are fried.
Serve as is or sprinkle with confectioners' sugar while still warm.