Step 1: Make the Pastry
For a 9 inch shell, you will need:
1 cup flour
1 tablespoon sugar
1/4 tsp salt
1/4 tsp grated lemon peel
1/2 cup unsalted butter, at room temperature
1 tablespoon water
1/2 tsp vanilla extract
1. Mix flour, sugar, salt and lemon peel in a medium sized mixing bowl. ()If using salted butter, omit the salt.)
2. Cut butter into 1/2 inch slices and work it into the flour mixture with your hands until the mixture takes on the form of lumpy cornmeal. The softer your butter is, the faster this will happen. You can also use a pastry blender, if you have one, but it's not necessary.
3. Combine the water and vanilla and work it into the flour-butter mixture until the pastry is just blended and will hold together if you press it.
4. Gather into a ball and wrap in plastic.
5. Let rest a room temperature for 30 minutes to allow the flour to absorb the moisture more completely. (At this point you can wrap in foil and freeze for up to a month.)
Step 2: Make the Custard
You will need:
2 lemons (any will do, though meyer lemons are spectacular here)
2 large eggs
3 large egg yolks
6 tablespoons sugar
2 tablespoons milk
1/4 tsp cornstarch (optional)
3 tablespoons unsalted butter
3 tablespoons salted butter
1. Whisk by hand the eggs and egg yolks with the sugar in a heavy, non-corroding saucepan until just mixed.
2. OPTIONAL: Mix the milk into the cornstarch in a small cup, then add to the egg mixture. The cornstarch is necessary if the filling is to brown properly when baking. If you do not want to brown the tart, the cornstarch can be omitted.
3. Grate the peel from the lemons into a small non-corroding bowl. Juice the lemons and strain the juice into the same bowl. Strain out seeds, but force as much as the pulp through the strainer as you can.
4. Stir juice mixture into the eggs: it will look a bit curdled when the juice is added, but will smooth out later.
5. Cut the butter into pieces and add to the mixture.
6. Cook over low to medium heat, stirring constantly in a figure eight motion, until it just coats the spoon and is the thickness of custard. A good way to tell it's done is to drag your finger along the back of the spoon. If it leaves a clear line, and the custard doesn't run back together, it's ready.
7. Remove from heat. Let stand 5 minutes to thicken, then whisk slightly to smooth out the custard.
8. Pour the filling into a bowl and chill while you pre-bake the tart shell. (This custard will keep as is in the the refrigerator for up to two weeks. It’s delicious!)
Step 3: Prepare the Crust
2. Press pastry evenly into the dish with your hands - the dough will be too soft to roll.
* A tip, here. Start by cutting the dough into thirds. Place one third in the middle of the pie dish, and press it out evenly into as large a circle as you can. Take the next third of dough, and place small pieces around the edge of the circle you've just made, pressing it out until the bottom of the pie dish is completely covered. Break the last piece of dough into smaller pieces, and roll between your hands to form long rolls. Space these evenly around the perimeter of the pie dish, and press flat, forming the sides. Be sure that the seams where two pieces meet are well joined.
2. Wrap in foil and freeze for 30 minutes or overnight.
Step 4: Bake the Crust
2. Bake the crust for about 25 min - rotating the tart once half way through - until the crust is light golden brown and baked all the way through. (You don’t need to fill the shell with beans before baking; this pastry doesn’t shrink much.)
Step 5: Bake the Tart
2. Fill the slightly cooled, pre-baked crust with filling and bake for 30-35 minutes, or until the top is speckled with dark brown spots and the filling has puffed slightly. Remove from the oven and cool on a rack in its pan. You can also bake the tart just long enough to set the filling, about 15-20 minutes. This will make a smooth, shiny tart.
Note: This tart is delicate. A too hot oven, even slightly so, will scorch the crust and boil the custard. Pay attention to the oven, turn the tart shell and tart half way through baking, and cover with aluminum foil if it’s browning (too much or at all, depending on the alternative you choose.)