In a large bowl, combine flour, sugar, baking powder, baking soda, cinnamon, and salt.
Cut in vegetable shortening using a pastry blender or a fork until mixture is crumbly.
Stir in raisins and buttermilk, stirring until dry ingredients are moistened. Note: if mixture seems too dry (it's not sticking together in a ball) add a little bit more buttermilk until the dough starts to hold together and not be so crumbly.
Roll dough to about ¾ inch thickness on a lightly floured surface and cut with a 3-inch biscuit cutter or a mini biscuit cutter, and place on a parchment paper lined baking sheet.
Make sure not to twist the biscuits as you cut them. Just push down and then lift the biscuit up.
Bake for about 10-15 minutes for 3-inch biscuits and for about 6-8 minutes for mini biscuits.
To make the glaze:, combine powdered sugar, milk, vegetable oil and cinnamon in a small bowl. Stir until completely mixed.
Drizzle over hot biscuits or dip the tops of the biscuits in the glaze. I like to double dip mine for a nice thick glaze on top!
Video
Notes
I found that these were tastiest when served warm. The glaze does harden up to a nice finish when it cools. Just pop these in the microwave for about 5 seconds to warm them up and serve.