To prepare biscuits:

1. Preheat oven to 450 degrees F.
2. Prepare a floured surface for shaping the dough.
3. Line an ungreased baking sheet with Silpat cookie sheet liner.
4. In a medium-sized bowl, whisk together the flour, sugar and salt.
5. Using a fork, cut the shortening and butter into the flour.
6. Working quickly, work the mixture only until crumbly.
7. Make a depression in the center of the flour mixture.
8. Pour the buttermilk into the depression.
9. Stir with a spoon, blending until the dough is tacky.
10. Turn the dough onto the floured surface.
11. Fold the dough over itself 3 times.
12. Shape the dough into a 3/4-inch thick disc.
13. Use a 2-inch biscuit cutter to create each biscuit.
14. Arrange biscuits on the baking sheet leaving space between them.
15. Reshape the scrap dough to continue making as many biscuits as possible.
16. Bake biscuits for 15-18 minutes, turning the sheet halfway through baking, until the tops are lightly golden.
17. Brush the tops of the biscuits with additional melted butter.

To prepare sausage gravy:

1. Heat a 4-quart heavy-bottomed saucepan over medium-high heat.
2. Crumble sausage into the pan, cooking until it browns, about 2 minutes.
3. Reduce heat to medium.
4. Break up the sausage, and continue to cook until browned through.
5. Stir in onions, and cook until they are transparent.
6. Sprinkle the flour over the sausage-onion mixture.
7. Stir the flour into the mixture, and cook 6-8 minutes.
8. Add poultry seasoning, ground nutmeg, Worcestershire sauce, Tabasco and salt.
9. Stir and cook for 1 minute.
10. Slowly add the milk, stirring occasionally.
11. Cook over medium heat until gravy has thickened, about 15 minutes.