Adapted from Baking From My Home To Yours (Page 331-333)
1/2 cup Splenda sugar blend
Zest of 4 limes
3/4 cup All Whites (4 eggs)
1/2 cup fresh lime juice
1/4 cup lemon juice
2 sticks lite butter, softened & cut into tablespoon pieces
9 inch tart shell (I used a recipe out of Betty Crocker Most Requested Recipes: Brunch and made it in a pie plate because I don't have a tart pan)
Have a thermometer, a strainer, and a blender at hand. Bring a few inches of water to simmer in a saucepan.
Put the Splenda and zest in a large heatproof bowl that can be set over the pan of simmering water. Off the heat, rub the Splenda and zest together between your fingers until the sugar is moist, grainy and very aromatic. Whisk in the eggs, followed by the lime and 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 cream until it reaches 180 degrees. As you whisk - you must whisk constantly to keep the eggs from scrambling - you'll see the cream will start out light and foamy, then the bubbles will get bigger, and then, ad it gets closer to 180 degrees, 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. It could take up to 10 minutes.
As soon as it reaches 180 degrees, remove the cream from the heat and drain it into the container of the blender; discard the zest. Let the cream stand, stirring occasionally, until it cools to 140 degrees, about 10 minutes.
Turn the blender to high and 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.
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 in the freezer for up to 2 months.)
When you are ready to assemble the tart, just whisk the cream to loosen it and spoon it into the shell. Serve the tart, or refrigerate until needed.
I made the cream the night before and put it in the fridge. It didn't thicken up as much as I would have liked it to. I assembled the tart and stuck it in the freezer to firm it up. It worked great!