01 -
Set the oven to 400°F and line a baking sheet with parchment paper.
02 -
In a large bowl, combine the flour, sugar, baking powder, baking soda, cinnamon, and salt.
03 -
Use a pastry blender or fork to cut in the shortening until the mixture becomes crumbly.
04 -
Stir in the raisins and buttermilk until the dry ingredients are just moistened. Add more buttermilk if the dough seems too dry.
05 -
Turn the dough onto a floured surface and roll it to about 3/4-inch thickness.
06 -
Use a 3-inch biscuit cutter to cut out the dough. Avoid twisting the cutter as you press down.
07 -
Place the biscuits on the baking sheet and bake for 10-15 minutes, or until golden brown.
08 -
In a small bowl, mix powdered sugar, milk, vegetable oil (if using), and cinnamon (if using) until smooth.
09 -
Drizzle the glaze over the hot biscuits or dip the tops into the glaze. For a thicker glaze, repeat after the first layer.