Preheat your oven to 325 degrees. Spray your mini muffin tin generously with non-stick baking spray. Set aside.
Using your stand mixer on medium-low speed, beat together the butter and sugar until just combined, for about 30 seconds. Add in the flour and salt, and beat together again for about one minute. Add in the water and raise the speed to medium-high, mixing until a dough forms, for a few minutes.
Using a lightly floured work surface, roll out dough to about 1/4 inch thickness. Using a 2 1/2 inch biscuit or cookie cutter, cut out the shells, (continuing to roll the dough scraps together and roll out again until you have all 24 shells). Gently place each one into the muffin tin cups, pressing gently to fill the bottoms and up the sides a bit. Bake for about 20 minutes, or until light golden brown. Let cool before removing from the muffin tin.