The Most Extraordinary French Lemon Cream Tart
Recipe Source: Baking: From My Home to Yours by Dorie Greenspan, page 331
1 cup sugar
Grated zest of 3 lemons (I used 3 large Meyer Lemons)
4 large eggs
3/4 cup fresh lemon juice (from 4-5 lemons) (Again, 3 Meyer Lemons were perfect)
3 sticks plus 5 tablespoons (10.5 ounces) unsalted butter, cut into tablespoon-size pieces, at room temperature
1 9-inch tart shell made with Sweet Tart Dough (page 444), Sweet Tart Dough with Nuts (page 444) or Spices Tart Dough (page 447), fully baked and cooled (I went with the plain Sweet Tart Dough which contrary to what the name would lead you to believe, has nothing at all to do with the candy Sweet Tarts. I still can't figure out what that would taste like...)
Getting Ready: Have an instant-read thermometer, a strainer and a blender (first choice) or food processor at hand. (I used a food processor and loved it. :) Bring a few inches of water to a simmer in a saucepan.
Put the sugar and zest in a large heatproof bowl that can be set over the pan of simmering water. (General consensus with the Tuesdays With Dorie group was that a stainless steel bowl works better than Pyrex or glass.) Off the heat, rub the sugar and zest together between your fingers until the sugar is moist, grainy and very aromatic. Whisk in the eggs, followed by the lemon juice.
Set the bowl over the pan and start stirring with the whisk as soon as the mixture feels tepid to the touch. Cook the lemon cream until it reaches 180 degrees F. As you whisk - you must whisk constantly to keep the eggs from scrambling - you'll see that the cream will start out light and foamy, then the bubbles will get bigger, and then, as it gets closer to 180 degrees F, it will start to thicken and the whisk will leave tracks. Heads up at this point - the tracks mean the cream is almost ready. Don't stop whisking or checking the temperature, and have patience - depending on how much heat you're giving the cream, getting to temp can take as long as 10 minutes. (Make sure your thermometer is calibrated or go by texture. With the instant laser read thermometer, I never got above 160 degrees F, but the cream was nicely thick. I gave it 4-5 minutes at that temp before calling it good. Oh, and it took closer to 20 minutes to reach this stage at almost 7000ft altitude. Your Mileage May Vary.)
As soon as it reaches 180 degrees F, remove the cream from the heat and strain it into the container of the blender (or food processor); discard the zest. let the cream stand, stirring occasionally, until it cools to 140 degrees F, about 10 minutes. (Mine was almost immediately cooler than 140 degrees F, most probably because I couldn't get it to 180 on heat.)
Turn the blender to high (or turn on the processor) and, with the machine going, add the butter about 5 pieces at a time. Scrape down the sides of the container as needed as you incorporate the butter. Once the butter is in, keep the machine going - to get the perfect light, airy texture of lemon-cream dreams, you must continue to blend the cream for another 3 minutes. If your machine protests and gets a bit too hot, work in 1-minute intervals, giving the machine a little rest between beats.
Pour the cream into a container, press a piece of plastic wrap against the surface to create an airtight seal and refrigerate for at least 4 hours or overnight. (The cream will keep in the fridge for 4 days or, tightly sealed, in the freezer for up to 2 months; thaw it overnight in the refrigerator.)
When you are ready to assemble the tart, just whisk the cream to loosen it and spoon it into the tart shell. Serve the tart, or refrigerate until needed.
Serving: It's a particular pleasure to have this tart when the cream is cold and the crust is at room temperature. A raspberrry (page 467) or other fruit coulis is nice, but not necessary; so is a little creme fraiche. I know it sounds odd to ffer something as rich as creme fraiche with a tart like this, but it works - because the lemon cream is so light and so intensley citric, it doesn't taste or feel rich.