- In a large bowl or food processor, whisk together the flour, salt, sugar (if using), and baking powder. 
- Cut the butter or cold Crisco into chunks before adding to the processing / using the pastry cutter.  I cut the butter in half, and then in half again (length-wise) and then cut slices... so I have nearly pea sized cubes to start - minimizes the need for the processor to warm up the butter and work more than it needs to.  
- Cut in the butter until the mixture resembles coarse crumbs with pea-sized bits—pulse if using a processor, or use a pastry cutter/forks by hand.  I added my butter in two steps (two sticks) so I didn't have to pulse too long making butter melty.   
- Stir the vinegar (if using) into the ice water.   
- Add ice water 1 tablespoon at a time, mixing lightly with a fork or pulsing the food processor until the dough just holds together when squeezed. The dough should look rough and clumpy.  
- Dump the dough onto a lightly floured counter and gently press into a cohesive ball—add a splash more water if it's too crumbly.  (Note my dough went from the prior picture to these clumps just by pressing the dough together into a lump.) 
- Divide dough into two portions (bottom slightly larger), flatten into disks, wrap in plastic, and chill in the fridge for at least 30 minutes.  Ideally an hour or two or even overnight.   
- When ready to bake - roll out on a floured surface to about 12 inches, fit into your pie pan, add filling, top with the second crust, crimp edges, and bake according to your pie recipe. For extra shine, brush with an egg wash before baking. 
- **I used my dough to top a Chicken Pot Pie.  See the cracks in the dough?  I didn't use quite enough water.  I think I used 5 Tbl - and probably could have used 6.  (Temp in the house / Temp Outside / Humidity levels - all play a part in how much water you need....)