For Ice Cream Base:
- 2/3 cup granulated sugar
- 1/2 cup Meyer lemon juice or 1/3 cup regular lemon juice
- 6 tablespoons unsalted butter, cut into 1/2-inch cubes
- pinch salt
- 3 large eggs, separated
- 3/4 cup heavy cream
- 3/4 cup whole milk
- 1/2 cup granulated sugar
- pinch cream of tartar
- 1/2 teaspoon vanilla extract
- Prepare an ice bath by placing a smaller bowl inside of a larger bowl filled with ice water. Set aside.
- Place sugar, lemon juice, butter, and salt in a medium saucepan. Slowly bring to a gentle boil over medium-low heat.
- In a bowl, whisk together egg yolks (reserve egg whites to make meringue later). Slowly ladle 1/4 cup at a time of warm lemon mixture into yolks, whisking vigorously, until about half of lemon mixture has been incorporated and yolk mixture is warm to the touch. Pour into saucepan with remaining lemon mixture, whisking to combine. Place over low heat and cook until thick enough to coat the back of the spoon, 2 to 3 minutes (mixture will read about 170-175 degrees on a instant-read thermometer). Remove from heat.
- Strain mixture through a fine mesh sieve to remove any bits of cooked egg, into bowl within ice bath. Stir in heavy cream and milk, and let sit, stirring occasionally, until cooled to room temperature. Cover bowl with a layer of plastic wrap, pressing plastic down onto surface of custard to prevent a skin from forming. Refrigerate until thoroughly chilled, at least 6 hours or overnight if possible.
- The next day, prepare the meringue. Place reserved 3 egg whites, sugar, and cream of tartar in the metal bowl of your stand mixer or other heat proof mixing bowl set over (but not touching) a pan of gently simmering water, whisking until mixture is frothy, warm to the touch, and sugar is completely dissolved (if you rub a bit between your fingers you should not feel any grains).
- Remove bowl from double boiler and dry bottom. Lock into stand mixer fitted with the whisk attachment, and turn on mixer to medium. After 1 minute, increase speed to medium high, then after another minute, increase to high speed. Whisk until meringue holds glossy peaks, and base of bowl is cool to the touch, about 10 minutes. Whisk in vanilla. Scoop meringue into a ziptop bag, pressing mixture into one corner and sealing well. Set aside.
- Prepare your ice cream maker and churn chilled ice cream base according to manufacturers instructions.
- When ice cream is almost done, trim off a 1/2-inch corner of the bag that holds the meringue. Depending on your ice cream setup you may have to briefly pause it, squeezing a portion of the meringue into the ice cream. Turn back on for a few seconds, then pause again to squeeze in more meringue. You are looking for a meringue 'swirl' here, don't mix it in fully.
- Once all of meringue has been swirled, transfer ice cream to an airtight freezer safe container, then place in freezer until completely firm, at least 4 hours or overnight if possible.
Read more at http://www.loveandoliveoil.com/2015/05/lemon-meringue-ice-cream.html