1. For the Crust: Add the flour, sugar and salt to a food processor and pulse until combined. Then add the butter and pulse the mixture again until it resembles a coarse meal. Add the egg yolks and drizzle the ice water over the mixture and pulse until the dough begins to come together. If dough is a little dry add a touch more water. Pat the dough into a round that is 1 inch thick, wrap it in plastic dough and chill it in the refrigerator for at least 2 hours, or up to 2 days.

2. To Bake the Crust: Preheat the oven to 375ºF. Roll the dough to 1/8 inch thick and press it into an 8-inch round tart pan, trimming the edges as necessary. Chill the dough for about 30 minutes, or until firm. Add some pie weights or dried beans on top of the crust and bake it until the edges turn golden, about 15 minutes. Remove the weights and bake the crust for another 10 to 12 minutes, then let it cool completely on a wire rack.

3. For the filling: Place the yolks, lemon zest, lemon juice and 1 cup of sugar in a small saucepan and bring the heat to medium. Whisk the ingredients constantly and cook until the mixture is thickened and a little bubbly. About 8 to 10 minutes. The mixture will thicken up just toward the end of the 8 minutes, it happens very quickly. Do not leave the mixture unattended or it could curdle! Pour the thickened mixture through a fine mesh sieve to strain out any lumpy bits and zest. Stir the cold butter pieces until the mixture until the lemon becomes thick, smooth and glossy. Pour the lemon filling into the cooled crust and refrigerate it, uncovered, for at least 2 hours. Or until set.

4. Right before serving, turn on the broiler. Scatter the remaining 2 tablespoons of sugar on top of the filling and place it under the broiler for about 2 to 3 minutes. The top will turn a caramel colored brown and will get a little bubbly. Do not let it burn! Remove the tart from the broiler, slice and serve.