Preheat oven to 350°F.
Melt the butter in the microwave and stir in 1 tablespoon lemon zest. Set aside for about 5 minutes, stirring a few times.
Combine the flour, ¼ cup sugar and a pinch of salt in the bowl of a food processor. Process until combined. Add the butter and zest mixture slowly, pulsing until the ingredients are blended.
Pour the crust mixture into an 11-inch tart pan with a removable bottom. Press the mixture using your fingertips evenly up the sides and on the bottom of the pan. (Make sure the crust goes to the top of the sides of the pan. The filling with rise to the edge of the top and you don’t want it to over flow.)
Bake for about 20 minutes or until the crust is light golden brown. Cool on a wire rack while preparing the filling.
Combine ¾ cup sugar, a pinch of salt, ¼ teaspoon arrowroot and the remaining 1 tablespoon lemon zest in the bowl of the food processor. Process until the zest is finely ground – about 2 or 3 minutes.
In a medium mixing bowl whisk the eggs. Add the sugar and lemon juice and whisk until smooth.
In a small bowl beat the ½ cup of whipping cream until soft peaks form. Gently whisk the cream into the egg and sugar mixture until blended. Carefully pour the filling into the warm crust and bake for 25 minutes or until the center is just set. Cool the tart completely and garnish with powdered sugar before serving.
Store leftovers in the refrigerator.