Whirl dry ingredients for crust in the bowl of a food processor. Add half the butter and process until you no longer see chunks. Add remaining butter and process briefly, leaving chunks the size of peanuts.
Working quickly, turn on the food processor and pour the ice water through the feed tube, stopping before the dough comes together. Pinch a bit of the dough between your fingers. If it does not stick together, add a little more water and whirl briefly.
Turn out the dough onto a large piece of plastic wrap. Use the plastic wrap to help you create a large, flat disk: fold the edges of the dough toward the center and press down to smooth out the roughness. Refrigerate dough for at least 30 minutes.
Roll the dough into a large circle about 1/8-inch thick. Using a 4 1/2 inch cutter, stamp out circles of dough (if using silicone tart pans, use a 5-inch cutter). If needed, reroll scraps to cut a total of 6 circles.
Nestle the rounds of dough into 4-inch tart pans with removable bottoms. Pick the bottom with a fork. Set the tart shells on a rimmed baking pan, cover with plastic wrap, and chill for at least one hour.