In a large mixing bowl, combine flour and salt, stir to mix. Add cubed butter and grated tallow. Cut into the flour with a large fork of pastry blender (aka pastry cutter). You are looking for a pebbly texture that varies in size. Work fast, and if you feel that the fats are melting, throw the entire bowl in the fridge to cool down before continuing. 

Once mixed, add in ice water a few tablespoons at a time. Start off with 2 to 3 tablespoons, mix by hand, then add 1 tablespoon at a time until you can form a ball with the dough. 

Roll the dough into a ball and split half. Wrap each half individually with plastic wrap, and refrigerate for an hour at least before rolling out. 

At this point, you can wrap the dough tight and refrigerate or freeze for later use or preheat the oven to 350°F and prepare a filling. 

Lightly flour your work surface and roll out one of the pie dough balls to a roughly 12-inch circle. Grease a 9-inch pie pan and place the pie dough in the pan. From here, if you're feeling fancy, you can make the edges of the pie crust pretty with ridges and folds, or if you're like me, just leave it rustic. Fill as you wish and enjoy!