Confectioner’s sugar or cinnamon sugar for tossing
In a heavy bottom, medium size pot, over medium heat, melt shortening and heat to to 325°F. This will take about 10 minutes.
In the meantime, in a medium bowl, whisk together sugar, oil and egg until combined, about 30 seconds. Whisk in the half and half, vinegar, and vanilla until combined.
Measure the flour, baking powder, salt, cinnamon and baking soda into the mixing bowl. Ditch the whisk for a sturdy spatula and toss only the dry ingredients on top together with the whisk first, before truly stirring them into the wet ingredients below. Mix all until just combined, but still sticky.
Refrigerate dough for an hour until it is firm enough to handle with your hands. Lightly flour a surface, pop the dough out of the bowl and press into roughly a 9-inch square, about 1/2 inch thick. Using cutters or the lips of a larger and smaller sized cup, cut out donut rounds with 4” diameters. (If you have any extra dough left after cutting out, stick it all together, press it out and repeat the process until you have used up all of the dough.)
Gently drop one donut hole into the hot fat to do a temperature check. It should sizzle immediately, float and become golden brown within 1-2 minutes. If it sinks, or doesn’t sizzle at all, the fat is not warm enough, so wait a few more minutes or turn up the heat a bit. If the donut hole fries too quickly and browns rather immediately, scoop some room temperature shortening into the pot to cool the overall temperature down, turn down the heat. Fry another donut hole until you reach the sizzle/float/golden brown in 1-2 minutes target. (Remove all these donut holes from the fat, obvi). Then fry a full donut round, gently placing the donut in the fat away from you so as not to splash up on you- it should sink then float within 10 Mississippis, sizzle and become golden brown within 3 minutes. Flip and fry the other side until golden brown 2-3 minutes.
Gently remove donut from fat and transfer to a paper towel lined baking tray, sprinkle both sides immediately with confectioners’ sugar or toss in a brown paper bag with cinnamon sugar and eat. Don’t you dare try to save a donut for later. Eat! Now!
Frying in Shortening yields the best donut texture: crispy exteriors for the win!