For best results, keep the shortening and butter very cold until ready to use. This helps create steam during baking, resulting in flakier layers.
If you don't have buttermilk, you can make a substitute by adding 1 tablespoon of lemon juice or vinegar to 1 cup of milk and letting it sit for 5 minutes.
Do not over-knead the dough, as this will make the biscuits tough. Just a few gentle kneads are enough to bring the dough together.
Store leftover biscuits in an airtight container at room temperature for up to 2 days, or freeze for longer storage. Reheat in a toaster oven or microwave.
For a savory twist, add 1/2 cup of shredded cheddar cheese and 1 teaspoon of dried herbs to the dry ingredients.