Place about 4 cups of vegetable oil in a heavy bottom pot and heat until it reaches 350°F. I like to leave my candy thermometer in the pot during frying so I can regulate the heat up or down if it gets to hot or cold. A heavy bottomed pot is best for frying, it’s easier to regulate the heat that way than with a thinner pot. (I use a Le Cruset soup pot.)
Cut each biscuit into four pieces and roll into balls between the palms of your hands. Fry in batches of 5-6 depending on the size of your pot. Cook 2-3 minutes until they are a deep golden, flipping halfway. Remove from oil using a slotted spoon and place the cooked donut holes on a cookie sheet topped with two layers of paper towels.
Make the Lemon Sugar Topping: stir together the lemon zest and sugar in a bowl. Cool donut holes until you can touch them before rolling in sugar.
Make the Lemon Glaze: whisk powdered sugar and lemon juice in a second small bowl. Let donut holes cool completely, then dip in glaze.
Makes enough sugar topping for 16 donut holes and enough glaze for 16 donut holes. Double if you wish to do all one or the other.