1. Pastry shell can be baked a day ahead. The tart keeps well, tightly wrapped, in refrigerator for two to three days. Serve at room temperature.
2. Making the Pastry in Food Processor: Combine the dry ingredients in processor fitted with steel blade. Blend for 10 seconds. Add butter and process until pastry looks like coarse meal. Add egg and process only until the dough is crumbly. Gather it into a ball and chill 30 minutes to overnight.
3. Making Pastry by Hand: In a shallow bowl stir together dry ingredients. Rub in butter with your fingertips or a pastry cutter, until there are just a few shales of solid butter left. Using a fork, toss in egg to barely moisten dough. Gather into a ball and chill 30 minutes to overnight.
4. Rolling Out and Prebaking Crust: Preheat oven to 400 degrees. Grease an 11-inch by 7/8 inch fluted, false-bottomed tart pan.
5. Generously flour a work surface. Roll out pastry to a 14-inch circle (the pastry and filling are of equal thickness in this tart) so it is about 1/4 inch thick. Fit into the tart pan. Dough is fragile, so do not worry if it breaks, just press pieces together in pan. No one sees the bottom of a tart shell.
6. Prick it with a fork and chill 30 minutes. Then line the crust with foil and weight with dried beans or rice. Bake 10 minutes. Remove liner, turn oven down to 350 degrees, and bake another 5 to 8 minutes, or until pale gold. Cool on a rack.
Making the Filling:
1. Have oven at 350 degrees.
2. Combine water and sugar in a 3-quart saucepan. Cook over medium heat until clear, brushing down sides of pan with a brush dipped in cold water.
3. Raise heat to high and bubble fiercely until the syrup becomes honey colored. Remove from the heat and stir in lemon zest and butter. Once the butter melts, stir in cream, liqueur, 1/3 cup water, and almonds. Set the pan over high heat for a few seconds to dissolve the caramel.
4. Stir in almond extract and pour into the pastry shell.
5. Baking and Serving: Bake 30 minutes and do not worry when the filling bubbles and seethes. All is as it should be. Just before removing from oven brush with the 2 tablespoons of liqueur.
6. Cool tart on a rack. Slice in wedges for serving.
Lynne Rossetto Kasper has won numerous awards as host of The Splendid Table, including two James Beard Foundation Awards (1998, 2008) for Best National Radio Show on Food, five Clarion Awards (2007, 2008, 2009, 2010, 2014) from Women in Communication, and a Gracie Allen Award in 2000 for Best Syndicated Talk Show.