Make the crust: Place the flour, confectioners sugar and salt in the bowl of a food processor fitted with the steel blade. Pulse a few times to combine all of the ingredients. Add in the cold butter pieces and pulse until the butter is coarsely cut into the flour--some pieces should be the size of peas, and others should be the size of oatmeal flakes. Add in the egg a little at a time, pulsing a few times after each addition. Once all the egg has been added, process the dough in long pulses--about 10 second increments--until the dough forms large clumps. When you are pulsing and the dough starts to come together, you will notice that the sound of your food processor will change--this is your cue to stop pulsing. Turn the dough out onto a work surface and knead it very lightly and quickly {3-4 times} to incorporate any ingredients that were not mixed in.

Butter the bottom and sides of a 9-inch fluted tart pan with a removable bottom. Press the dough evenly over the bottom and up the sides of the tart pan using your hands. Once the crust has been pressed evenly into the pan, freeze the crust for a minimum of 30 minutes, but preferably longer.

Hat the oven to 375 degrees. Butter a piece of aluminum foil. Remove the tart pan from the freezer and transfer it to a baking sheet. Cover the tart crust with the piece of buttered aluminum foil, pressing it tightly against the crust. Bake the crust for 25 minutes. Remove the foil. If you notice that the crust has puffed up, gently press it down with the back of a spoon.

For a partially baked crust, remove the crust from the oven and allow it to cool completely after this step. Proceed with the instructions for your chosen recipe.

For a fully baked crust: After removing the foil, bake the crust for an additional 8-10 minutes, until it is firm and golden brown. Keep a careful eye on the crust towards the end of baking, as it can burn very quickly. Remove the crust from the oven and allow it to cool completely before filling it with the lime curd. Keep the tart refrigerated until ready to serve to allow the curd to set in the tart crust.

Make the filling: Begin by peeling each lime using a vegetable peeler being careful not to peel away the white pith. Set the zest aside. Juice the limes until you have 1/2 cup of lime juice. Set aside.

Place the granulated sugar and the lime zest in the bowl of a food processor fitted with the steel blade. Pulse the sugar and zest until the ingredients are evenly incorporated and the zest is broken into small bits throughout the sugar.

Transfer the lime zest-sugar mixture into the bowl of a stand mixer fitted with the paddle attachment and add in the butter. Cream the butter and sugar mixture over medium speed until the butter is completely incorporated into the sugar. Over low speed, add in the eggs, one at a time, mixing well after each addition. Add in the lime juice and then the salt, mixing until evenly incorporated. Transfer the mixture into a 2 qt. saucepan and cook over low heat, stirrling continuously until the mixture has thickened, about 10 minutes. Do not bring the mixture to a simmer/boil.

Once the curd is cooked, remove it from the heat and place a lid on the saucpan and let the curd cool in the saucepan for 20-30 minutes before transfering it to a glass jar. Allow the curd to cool completely to room temperature before using or refrigerating it. If you refrigerate it, allow the curd to come to room temperature before serving for the best flavor.